user manual COSMIN Risk of Bias tool v4 JAN final · 2021. 1. 16. · 6 1. Background information...

COSMINRiskofBiastooltoassessthequalityofstudiesonreliabilityandmeasurementerrorofoutcomemeasurementinstrument

usermanual

Version1.0datedJanuary2021

LidwineBMokkinkMaartenBoers

CeesvanderVleutenDonaldLPatrickJordiAlonsoLexMBouter

HenricaCWdeVetCarolineBTerwee

ContactLBMokkink,PhDAmsterdamUMC,VrijeUniversiteitAmsterdam,DepartmentofEpidemiologyandDataScienceAmsterdamPublicHealthresearchinstituteDeBoelelaan1117,1081BTAmsterdamTheNetherlandsWebsite:www.cosmin.nlE‐mail:w.mokkink@amsterdamumc.nl

ThedevelopmentoftheCOSMINRiskofBiastooltoassessthequalityofstudiesonreliabilityandmeasurementerrorwaspartoftheVENIprogrammewithprojectnumber91617098,fundedbyZonMw(TheNetherlandsOrganisationforHealthResearchandDevelopment).

TableofContent

Foreword 5

1. Backgroundinformation 6

1.1 COSMINinitiativeandsteeringcommittee 6

1.2Howtocitethismanual 7

1.3DevelopmentoftheCOSMINRiskofBiastooltoassessthequalityofstudiesonreliabilityandmeasurementerror

1.4 Definitionsofreliabilityandmeasurementerror 7

1.5 FocusoftheCOSMINRiskofBiastool 8

1.6ThestructureoftheCOSMINRiskofBiastool 10

1.7 The“worst‐score‐counts”method 10

1.8 Relevanceoftheresearchquestion 11

1.9 UsingtheCOSMINRiskofBiastoolinasystematicreview 11

1.10Expertiserequiredforusingthetool 12

1.11UsingtheCOSMINRiskofBiastooltoassessstudiesonPROMsorObsROMs

1.12ARiskofBiastoolisnotastudydesignchecklist,norareportinggiudeline

2. PartA.Understandinghowastudyinformsusaboutthereliabilityandmeasurementerrorofanoutcomemeasurementinstrument

2.1 Componentsofoutcomemeasurementinstruments 14

2.2 Extractingtheelementsofacomprehensiveresearchquestion 20

2.3 ExampleofhowtousePartAoftheCOSMINRiskofBiastooltoassessthequalityofastudybySkeieetal.(2015)

3. PartB.Assessingtheriskofbiasofastudyonreliabilityormeasurementerror

3.1Elaborationonstandardsforstudiesonreliability 33

3.2Elaborationonstandardsforstudiesonmeasurementerror 40

3.3ExampleofhowtousePartBoftheCOSMINRiskofBiastooltoassessthequalityofastudybySkeieetal.(2015)

4. UsingtheCOSMINRiskofBiastoolinasystematicreviewofoutcomemeasurementinstruments

4.1Theeleven‐stepprocedureforconductingasystematicreviewofClinROMs,PerFOMs,orlaboratoryvalues

Appendix1.DataExtractiontableofrelevantinformationforeachincludedstudyinasystematicreview.

Appendix2.RiskofBiasratingsperstandardperstudy 62

Appendix3.ExampleofaFlow‐chart 63

Appendix4.Exampleofreportingtableoncharacteristicsoftheincludedmeasurementinstruments.

Appendix5.Exampleofreportingtableoncharacteristicsofthestudypopulations. 65

Appendix6.OverviewTableofqualityandresultsofstudiesonreliabilityandmeasurementerror.

Appendix7.SummaryofFindingsTablesforReliabilityandMeasurementerror. 67

References 68

ForewordTheCOSMINRiskofBiastooltoassessthequalityofstudiesonreliabilityandmeasurementerrorwasdevelopedtotransparentlyandsystematicallyassessthemethodologicalqualityofstudiesonreliabilityandmeasurementerrorofalltypesofoutcomemeasurementinstruments.ItisanextendedversionoftheCOSMINRiskofBiaschecklistfortheboxesreliabilityandmeasurementerrorforPROMs(1).Itwasdevelopedforclinician‐reportedoutcomemeasures(ClinROMs)(includinge.g.readingsbasedonimagingmodalitiesandratingsbasedonobservations),performance‐basedoutcomemeasurementinstruments(PerFOMs),orbiomarkers–alsocalledlaboratoryvalues(2,3).ThesemeasurementinstrumentsaremorecomplexthanPROMs,asnotonlypatientsareinvolved,butalsoprofessionals,andsometimes(complex)devices.Specificallyinstudiesonreliabilityandmeasurementerrortheseadditionalsourcesofvariationcomplicatethedesignofthesestudiesandmayinfluencetheirquality.Asdifferentsourcesofvariationcanplayarole,differentstudiescanbeconductedtoassessthereliabilityormeasurementerrorofanoutcomemeasurementinstrument.Toassessthequalityofsuchastudy,oneshouldunderstand(1)howtheresultsofapublishedstudyonreliabilityormeasurementerrorinformusaboutthereliabilityandmeasurementerroroftheoutcomemeasurementinstrumentunderstudy,and(2)whetherwecantrusttheresultfoundinthestudybyassessingtheriskofbiasofthestudy.ThesetwostepsarereflectedinthenewCOSMINRiskofBiastooltoassessthequalityofstudiesonreliabilityormeasurementerrorofoutcomemeasurementinstruments(4).Thequalityassessmentofastudyonreliabilityormeasurementerrorcanbeconductedinthecontextofasystematicreviewofoutcomemeasurementinstruments.Insuchareviewallmeasurementpropertiesareconsidered,thequalityoftheeachstudyisassessed,theresultsofthestudiesareextracted,andpermeasurementpropertyanoverallconclusionisdrawnaboutthequalityoftheinstrumentbasedonallavailableevidenceforeachmeasurementinstrument.Subsequently,thequalityoftheevidenceisgraded,takingthenumber,quality,and(consistencyof)resultsofthestudiesintoaccount.Arecommendationforthemostsuitableinstrumentismade,basedonquality,feasibilityandinterpretabilityofeachinstrument.Asthisisnotaneasytasktoperform,weencouragetousesystematicandtransparentmethodswhenconductingsuchsystematicreviews.WedevelopedtheCOSMINmethodologyforconductingsystematicreviewsofPROMS(5),includingtheCOSMINRiskofBiaschecklist(1,6).Whenconductingasystematicreviewofothertypesofoutcomemeasurementinstruments,suchasClinROMs,PerFOMs,orlaboratoryvalues,thisnewlydevelopedCOSMINRiskofBiastooltoassessthequalityofstudiesonreliabilityandmeasurementerrorcanbeincorporatedintotheCOSMINmethodology.Inthismanualwewillexplainhowthisnewtoolshouldbeused.

1. Backgroundinformation

1.1 COSMINinitiativeandsteeringcommittee

TheCOSMINinitiativeaimstoimprovetheselectionofhealthmeasurementinstrumentsbothinresearchandclinicalpracticebydevelopingtoolsforselectingthemostsuitableinstrumentforagivensituation.COSMINisaninternationalinitiativeconsistingofamultidisciplinaryteamofresearcherswithexpertiseinepidemiology,psychometrics,andqualitativeresearch,andinthedevelopmentandevaluationofoutcomemeasurementinstrumentsinthefieldofhealthcare,aswellasinperformingsystematicreviewsofoutcomemeasurementinstruments.ThistoolwasdevelopedinaDelphistudy(4).Thesteeringcommitteeofthisstudyconsistedof:LidwineBMokkinkMaartenBoersCeesvanderVleutenDonaldLPatrickJordiAlonsoLexMBouterHenricaCWdeVetCarolineBTerweeWeareverygratefultoallthepanelistsofthisstudy,whoprovideduswithmanyhelpfulandcriticalcommentsandarguments(inalphabeticalorder):M.A.D’Agostino,DorcasBeaton,SophievanBelle,SandraBeurskens,KristieBjornson,JanBoehnke,PatrickBossuyt,DonBushnell,StefanCano,SaskialeCessie,AlessandroChiarotto,MikeClark,JonDeeks,IrisEekhout,JimFarnsworthII,OkeGerke,SabineGoldhahn,RobertM.Gow,PhilipGriffiths,CristianGugiu,Jean‐BenoitHardouin,DesiréevanderHeijde,I‐ChanHuang,EllenJanssen,BrianJolly,LarsKonge,JanKottner,BrittanyLapin,HannekevanderLee,MariskaLeeflang,NancyMayo,SueMallett,JoyC.MacDermid,GeertMolenberghs,HolgerMuehlan,KoenNeijenhuijs,RaymondOstelo,LauraQuinn,DennisRevicki,JussiRepo,JohannesB.Reitsma,AnneW.Rutjes,MohsenSadatsafavi,DavidStreiner,MatthewStephenson,BerendTerluin,ZyphanieTyack,WernerVach,GemmaVilagutSaiz,MarcK.Walton,MatthijsWarrens,andDanielYeeTakFong.

1.2 Howtocitethismanual

ThismanualaccompaniesthetooldevelopedintheDelphistudy.Please,refertothearticlewhenusingthemanualoftheCOSMINRiskofBiastooltoassessthequalityofstudiesonreliabilityandmeasurementerror.LBMokkink,MBoers,CPMvanderVleuten,LMBouter,JAlonso,DLPatrick,HCWdeVet,CBTerwee.COSMINRiskofBiastooltoassessthequalityofstudiesonreliabilityormeasurementerrorofoutcomemeasurementinstruments:aDelphistudy.BMCMedicalResearchMethodology.2020;20(293).1.3 DevelopmentoftheCOSMINRiskofBiastooltoassessthequalityofstudieson

reliabilityandmeasurementerror

ThisCOSMINtoolwasdevelopedinaDelphistudy,containingthreerounds.Formoreinformationaboutthemethodsofthisstudy,werefertoMokkinketal.2020.InthisDelphistudywereachedconsensusonhowtoformulateacomprehensiveresearchquestionforstudiesonreliabilityandmeasurementerror,oncomponentsofoutcomemeasurementinstruments(whicharethepotentialsourcesofvariationrelevantinstudiesonreliabilityandmeasurementerror),andonstandardstoassessthequalityofastudyonreliabilityandmeasurementerrorofClinROMs,PerFOMs,orlaboratoryvalues.Basedonthoseresults,wedevelopedtheCOSMINRiskofBiastoolwhichcomprisestwoparts:1)sevenelementsthatmakeupacomprehensiveresearchquestionofthestudy,whichinformsusonhowthereliabilityandmeasurementerroroftheoutcomemeasurementinstrumentwasstudied,and2)standardsondesignrequirementsandpreferredstatisticalmethodsofstudiesonreliabilityandmeasurementerror,whichcanbeusedtoassessthequalityofthestudy.1.4 Definitionsofreliabilityandmeasurementerror

Reliabilityandmeasurementerrorareimportantmeasurementpropertiesofoutcomemeasurementinstruments.Reliabilityandmeasurementerroraredeterminedbasedonthesamestudydesignanddatacollection,butwithdifferentstatisticalmethods.Thesemeasurementpropertiesarethereforerelated,butdistinct.Reliabilityisdefinedastheproportionofthetotalvarianceinthemeasurementwhichisduetotruedifferencesbetweenpatients(7).Itreferstowhatextendaninstrumentisabletodistinguishbetweenpatients;areliabilitystudyinvestigatestheextenttowhichdifferentsourcesofvariationinfluencethemeasurement.Thisgivesdirectionforhowtoimprovethemeasurement,forexamplebystandardizationorrestrictionofthesourceofvariation.ReliabilitycanbecalculatedwithanIntra‐classCorrelation

Coefficient(ICC),aGeneralizabilityCoefficientorwithakappa.Reliabilityparametersareexpressedasaproportionandliesbetween0and1.Measurementerrorisdefinedasthesystematicandrandomerrorofapatient’sscorethatisnotattributedtotruechangesintheconstructtobemeasured(7).Itreferstohowclosethescoresofrepeatedmeasurementsinstablepatientsare;suchstudiesinvestigatetheabsolutedeviationofthescoresortheamountoferrorofrepeatedmeasurementsinstablepatients.Incaseofcategoricaloutcomesitisalsocalled‘agreement’.ForcontinuousoutcomesmeasurementerrorisexpressedinthemeasurementunitsofthemeasurementinstrumentwithaStandardErrorofMeasurement(SEM)orLimitsofAgreement(LoA).Forcategoricaloutcomesagreementisexpressedaspercentagetotalagreementorpercentagesspecific(e.g.positiveandnegative)agreement.1.5 FocusoftheCOSMINRiskofBiastoolWefocusonoutcomemeasurementinstruments,definedasinstrumentsusedtomonitorthehealthstatusof(agroupof)peopleovertime,forexampleinaclinicaltrialorinclinicalpractice.

Severaltypesofmeasurementinstrumentsexist,suchaspatient‐reportedoutcomemeasure(PROM);observer‐reportedoutcomemeasures(ObsROMs;i.e.proxymeasures);clinician‐reportedoutcomemeasurementinstruments(ClinROMs)(includinge.g.readingsbasedonimagingmodalitiesandratingsbasedonobservations);performance‐basedoutcomemeasurementinstruments(PerFOMs);andbiomarkeroutcomes–alsocalledlaboratoryvalues(2).TheCOSMINRiskofBiastooltoassessreliabilityandmeasurementerrorisspecificallydevelopedforClinROMs,PerFOMs,andlaboratoryvalues(seeTable1forexamples).Theseoutcomemeasurementinstrumentstypicallyrequireinvolvementofoneormoreprofessionalstooperateequipmentortools,togiveinstructionstothepatient(e.g.toperformataskoraction)ortocometoascorethroughtheirclinicalexpertise(e.g.afterobservingapatientoranimage).Anoutcomemeasurementinstrumentcomprisesthewholemeasurementproceduretocometoascore,includingissuessuchasmaterials,communication(e.g.instructionsandmotivatingpatientsincaseofperformance‐basedtest),clinicaljudgment,performingatask.Allissuesrelevantforreliableandvalidmeasurementshouldbedescribedinthemeasurementprotocolofanoutcomemeasurementinstrument.

Table1.ExamplesofClinROMs,PerFOMs,andlaboratoryvaluesClinician‐reportedoutcomemeasurementinstruments(ClinROMs)Clinician‐reportedratingoftheseverityofadiseaseorcondition.Forexample,theHamiltonAnxietyRatingScaletoassesstheseverityofanxietysymptomscomprises14itemsthatarescoredbyaclinician(8).AGlobalAssessmentoftheseverityofaconditionscorede.g.onasingle‐itemVisualAnalogueScalebyahealth‐careprofessional.Resultofclinicalexaminationof(patho)physiology,suchasbloodpressureoracountofswollenjoints.Clinicalreadingofdevice‐basedresults(oftenimaging),suchpowerDopplerultrasonographytoassessscardiacstructure,functionandhemodynamics(echocardiography)(9),orMRIusedtoevaluatecartilagedefectsize,depth,andsubchondralboneinordertoassesschondralandosteochondrallesionsattheknee(10).Performance‐basedoutcomemeasurementinstrument(PerFOMs)Aperformance‐basedwalkingtest(e.g.thetimed25‐footwalktest(11)),inwhichaprofessionalinstructsapatienttowalk25feetathisowncomfortablepacewithorwithoutawalkingaid.Timeneededtocover25feetismeasuredbytheprofessional.LaboratoryvalueorbiomarkerLaboratoryvaluesuchasHbA1c(glycatedhaemoglobin)measuredbytheturbidimetricinhibitionimmunoassay(TINIA)(12).DifferentversionsoroperationalizationsofoutcomemeasurementinstrumentsTomeasureaspecificconstruct,differentversionsofameasurementinstrumentmayexist.Forexample,theDoloplusisaclinicalassessmenttooltomeasurebehaviouralpainassessmentincognitivelyimpairedpatients,andisadministerede.g.bytheattendingnurse.TheoriginalDoloplus‐1contained15items,whiletheDoloplus‐2contains10items(13).Ameasurementinstrument(i.e.themeasurementprotocol)canbeoperationalizedinmanydifferentways,andeachoperationalizationcouldbeconsideredadifferentversion.Forexample,thespecificequipmentusedtomeasuretherangeofmotion(ROM)candiffer,e.g.,asimpleuniversalgoniometer(14)oranelectromagnetic3‐dimensionaltrackingsystem(15).Thelocationtobemeasuredcandiffer,e.g.,theneck(14)ortheshoulder(16).Thebackgroundoftheprofessionalinvolvedcandiffer,e.g.,arheumatologistoraradiologistwhoconductsthemeasurement,andtheseratersmayhavehaddifferentlevelsoftraining(17).Inprinciple,weconsidereachversionofanoutcomemeasurementinstrumentoreachdifferentoperationalizationofthemeasurementprotocolasaseparatemeasurementinstrument,untilevidenceisprovided(e.g.testingofmeasurementinvariance,orreliability)thattheversionsperformsimilarly.

1.6 ThestructureoftheCOSMINRiskofBiastool

TheCOSMINRiskofBiastoolcomprisestwoparts.PartAhelpstounderstandhowtheresultsofapublishedstudyinformusaboutthereliabilityormeasurementerroroftheoutcomemeasurementinstrumentsunderstudy.PartBhelpstoassesswhetherwecantrusttheresultobtainedinthestudybyassessingtheriskofbiasofthestudy.PartAForagoodunderstandingofhowtheresultsofastudyinformsusaboutthereliabilityandmeasurementerroroftheinstrument,agoodunderstandingofthedesignofthestudyanditscorrespondingcomprehensiveresearchquestionisneeded.InpartAwedescribethesevenelementsthatwerecommendtobeextracted,andthattogethercanbeusedtoconstructacomprehensiveresearchquestionforeachanalysis.Inaddition,PartAofthetoolcontainsanoverviewofthecomponentsofoutcomemeasurementinstruments.Thesecomponentarethepotentialsourcesofvariationthatcaneitherbestudied(i.e.variedacrosstherepeatedmeasurements),orarekeptorassumedtobestable(i.e.standardized).PartB.Next,wedevelopedtwoboxeswithstandardsforstudiesonreliabilityandforstudiesonmeasurementerror,respectively.AsintheCOSMINRiskofBiaschecklistforPROMs(1),standardsrefertodesignrequirementsandpreferredstatisticalmethodsofstudiesonmeasurementproperties.Forexample,‘reliabilityandmeasurementerrorshouldbeassessedinpatientsthatareassumedtobestable’;or‘measurementerrorshouldbeassessedwiththestandarderrorofmeasurementorwiththelimitsofagreement’.Thestandardsarestatedasquestions:e.g.‘werepatientsstableintheinterimperiodontheconstructtobemeasured?’.Wereferto‘preferred’statisticalmethods.Wemeanby‘preferred’thatthesestatisticalmethodsareappropriatetousewhenevaluatingreliabilityormeasurementerrorofoutcomemeasurementinstruments,andarecommonlyused.Othermethodsmaybeappropriatetouseaswell(forexamplebi‐factormodelsorMulti‐TraitMulti‐Method(MTMM)analyses,ornewlydevelopedmethods).Itisnotourintentiontocomprehensivelydescribeallpossiblestatisticalmethods,rathertodescribetheadequatemethodsthatarecommonlyusedintheliterature.ItisuptotheuseroftheCOSMINtoolhowstudiesusingtheselesscommonlyusedmethodsareassessed.1.7 The“worst‐score‐counts”principle

Eachstandardinaboxisscoredonthefour‐pointscale,i.e.‘verygood’,‘adequate’,‘doubtful’,and‘inadequate’,seechapter3formoreinformation.SimilarasintheCOSMINRiskofBiaschecklistforPROMs(1),weusetheworst‐score‐countsmethod(18)tocometoaratingforthequalityofthestudyonreliabilityormeasurementerror.

1.8 Relevanceoftheresearchquestion

Whilemanydifferentresearchquestionsconcerningthereliabilityormeasurementerrorofanoutcomemeasurementinstrumentcanbeinvestigated,therelevanceofastudyisnotunderquestionwhenusingthistool.Therelevanceofastudyreferstodifferentaspects.

‐ Choiceofthepotentialsource(s)ofvariationthathasbeenvariedovertherepeatedmeasurements.

‐ Choiceofthetargetpopulationofpatientsandprofessionals(whenapplicable)ofthestudy.

‐ Choiceofhowthemeasurementprotocolwasexecuted,whenapplicable.‐ Choiceofevaluatingthespecificmeasurementproperty,eitherreliabilityor

measurementerror.Oftenonlyreliabilityisreported,whilethemeasurementerrorcanbecalculatedusingthesamedata.

WhenusingthisCOSMINRiskofBiastool,theseaspectswillbeextractedfromthedesignofthestudy(inpartA).However,nojudgementwillbegivenabouttheappropriatenessofthechoicesmade.Thechoicesmadeintheresearchquestionandstudydesignbytheresearchersdeterminetheinterpretationandgeneralizabilityoftheresults.1.9 UsingtheCOSMINRiskofBiastoolinasystematicreview

TheCOSMINRiskofBiastoolisdevelopedtoassessthequalityofapublishedstudy.OneapplicationoftheCOSMINRiskofBiastoolistoassessthequalityofstudieswhenconductingasystematicreviewonmeasurementinstruments.COSMINdevelopedasystematicmethodologyforconductingsystematicreviewsofPROMs(5).Itconsistsofa10stepprocedure,inwhichtheCOSMINRiskofBiaschecklist(1)(containingstandardsforallninemeasurementproperties)canbeappliedtothestudiestoassessthequalityofeachstudy.TousetheCOSMINmethodologyforconductingsystematicreviewsofothertypesofinstruments–thatis:otherthanPROMs–weadvisetoreplacetheboxes6(Reliability)and7(Measurementerror)withtheCOSMINRiskofBiastooltoassessthequalityofstudiesonreliabilityandmeasurementerrorofoutcomemeasurementinstruments.MoreinformationabouthowtoconductasystematicreviewusingthenewCOSMINRiskofBiastoolcanbefoundinchapter4.

1.10 Expertiserequiredforusingthetool

Toassessthequalityofastudyonreliabilityandmeasurementerror,i.e.foruseinasystematicreviewonthequalityofoutcomemeasurementisquitecomplexandtimeconsuming,anditrequiresexpertisewithintheresearchteamonseveralaspects.Werecommendthatatleastoneoftheteammembersshouldhaveexpertiseontheconstructtobemeasured,e.g.tounderstandwhatappropriatetimeintervalsarebetweenrepeatedmeasurements;onthemeasurementinstruments,e.g.tounderstandwhatconcomitantsourcesofvariationcouldbe(andtheseshouldberestrictedorstandardized–seeelement2inPartA);onthepatientpopulation,e.g.tounderstandwhetherpatientswerestablebetweenrepeatedmeasurementsorwhethersubgroupsofpatientscanbeconsideredinonestudy.Aclinicalexpertmightcombinetheseexpertises.Amethodologicalexpertshouldbepartoftheteammemberwithexpertiseonthetheoryofreliabilityandmeasurementerror,e.g.tounderstandwhetherthedesignisappropriatelyanalyzed(e.g.standards7).1.11 UsingtheCOSMINRiskofBiastooltoassessstudiesonPROMsorObsROMs

ThisnewCOSMINRiskofBiastoolisdevelopedspecificallyforClinROMs,PerFOMs,andlaboratoryvalues.However,itcanalsobeusedtoassessthequalityofstudiesonreliabilityormeasurementerrorofPROMsorobserver‐reportedoutcomemeasures(ObsROMs;i.e.observationsmade,appraised,andrecordedbyapersonotherthanthepatientwhodoesnotrequirespecializedprofessionaltraining(2),e.g.proxymeasures).However,forthesetwotypesofinstrumentsthetoolmayseemunnecessarilycomplex.Thefirststepinthetool(i.e.understandinghowtheresultsinformusonthequalityofthemeasurementinstrumentunderstudy)isoftenobvious,astheaimofreliabilitystudiesofPROMsandObsROMsismostoftentoassesstest‐retestreliabilityormeasurementerrorofthewholemeasurementinstrument(asthesemeasurementinstrumentscanonlybetakeninonego,andtheonlypotentialsourceofvarianceisoccasion).Thesecondstepinthetool(assessingthequalityofthestudyusingthestandards)willleadtothesameratingcomparedtousingthestandardsoftheRiskofBiaschecklistforPROMs.Thestandardsondesignrequirementsinbothtoolsarepartlythesame.However,thenewtypesofoutcomemeasurementinstrumentsforwhichweadaptedtheCOSMINchecklist(i.e.ClinROMs,PerFOMsandlaboratoryvalues),requireadditionalstandards,whicharenotusuallyapplicableforPROMsandObsROMs.(Ifitisapplicableinaspecificstudy,itcouldberatedusingthe‘otherflaws’standardintheRiskofBiaschecklistforPROMs).Theresponseoptionsforstandardsonpreferredstatisticalmethodsinthenewtoolaresomewhatdifferentlyformulated,butwillleadtothesameratingasthePROMRiskofBiaschecklist.

1.12 ARiskofBiastoolisnotastudydesignchecklist,norareportingguideline

ThisCOSMINRiskofBiastoolisdevelopedtoassessthequality(i.e.riskofbias)ofapublishedstudyonreliabilityormeasurementerror.Thistoolisnotdevelopedasadesignchecklistorareportingguideline.Whendesigningorreportingastudyonreliabilityormeasurementerroradditionalitemsarerelevanttoconsiderorreport.Forexample,thesamplesizeofpatientsamplesandnumberofratersorrepeatedmeasurementsareimportantinthedesignofastudy,andwhenreportingspecificresultssuchasthevariancecomponents,95%confidenceintervalsaroundICCs,marginalwhenreportingkappa’s,oradditionalassumptionsarerequired.

2. PartA.Understandinghowastudyinformsusaboutthereliabilityandmeasurementerrorofanoutcomemeasurementinstrument.

Ingeneral,thedesignofastudyonreliabilityandmeasurementerrorisaboutrepeatedmeasurementinstablepatients.Eachmeasurementisaccompaniedbysomeerror.Thiserroriscausedbysourcesofvariation,suchastheequipmentused,theprofessionalsinvolved,andothercomponentsofmeasurementinstruments.Forexample,thescoreonaninstrumentcanbeinfluencedbyhowtheratermotivatesthepatient,howthemachinewassetup,orbytheoccasion(e.g.firstandsecondoccasion,dayoftheweek,timeoftheday).Inchapter2.1wesystematicallydescribeallcomponentsofoutcomemeasurementinstruments,whicharethepotentialsourcesofvariationofanoutcomemeasurementinstrument.Manydifferentsourcesofvariationcanaffectthemeasurement,andeachofthemcanbestudiedusingadifferentstudydesigns.Eachstudydesignanswersadifferentresearchquestion,andeachresearchquestiongivesspecificinformationaboutthequalityofthemeasurementinstrument.Tounderstandhowastudycaninformusaboutthequalityofanoutcomemeasurementinstrumentwedescribeinchapter2.2sevenelementsofacomprehensiveresearchquestion.PartAofthetoolcontainstheoverviewsofthecomponentsofoutcomemeasurementinstruments(foroutcomemeasurementinstrumentsthatdoesnotinvolvebiologicalsampling,andthosethatinvolvebiologicalsampling,respectively),andthesevenelementsofacomprehensiveresearchquestion.Inchapter2.3weprovideanexampleinwhichweshowhowtousePartAofthetool,byapplyingittoapaperbySkeie(19).Inchapter2.2wewillusethisexample,too(amongotherexamples).

2.1 Componentsofoutcomemeasurementinstruments

Allmeasurementinstrumentsconsistofcomponents,suchasequipmentandpreparatoryactions.Wedevelopedtwotaxonomiesofcomponentsofoutcomemeasurementinstruments,oneforoutcomemeasurementinstrumentsthatdonotinvolvebiologicalsampling(i.e.ClinROMsandPerFOMs)(seeTable2),andoneforthosethatdo(i.e.thelaboratoryvalues,suchasbloodorurinetests,tissuebiopsy)(seeTable3).

Table2.ComponentsofoutcomemeasurementinstrumentsthatdonotinvolvebiologicalsamplingComponent Elaboration Examples

Equipment Allequipmentnecessaryinthepreparation,theadministration,andtheassignmentofscoresoftheoutcomemeasurementinstrument

Questionnaireforms,computers,tablet,penandpaper;stairstepsofaspecificheight;deviceortools(suchasstopwatch,probe,tube);ultrasoundmachine,ultrasoundgels,MRIscanner;software.

Preparatoryactionsprecedingrawdatacollectionbyprofessionals,patients,andothers(ifapplicable)

1.Generalpreparatoryactions,suchasrequiredexpertiseortrainingforprofessionalstoprepare,administer,storeorassignthescores2.Specificpreparatoryactionsforeachmeasurement,suchas

preparationsofequipment,environment,storagebyprofessionalsa

preparationsofthepatientbbytheprofessional

Training,educationorexperiencerequired,certification.Preparationofequipment:calibrationofdevice/equipment,adjustsettingsofthemachine.Preparationoftheenvironment:lightconditions,roomtemperature,humidity,specificlengthofawalkingtrack.Preparationforstorage:designdatabaseandlogbookProvidegeneralandpreparatoryinstructionsforthepatients,suchasexplainingthetasks/actionthatneedtobeperformedincludingtimeschedule,safetyissuesandsideeffects;instructionsondiet(e.g.useofcaffeine),clothing(e.g.comfortableshoes,nojewelry,glassesordevices),performanceduringtests(e.g.performataskasusual;trytowalkasfastasyoucan;lieascalmaspossible);setsometrainingorperformafamiliarizationsession.Attachingelectrodestothebody,injectionwithradioactivesubstanceorcontrastdye,positioningthepatient,applyingultrasoundgel.

Component Elaboration Examples

Preparationsundertakenbythepatients

Listentoandunderstandingtheinstructionsprovided;adherencetothepreparatoryinstructionssuchasfasting,resting,takingmedication,bowelpreparation,exercising,shaving.

Collectionofrawdata

Allactionsundertakenbypatientandprofessional(s)tocollectthedata,beforeanydataprocessing

Thepatientcompletingquestionsathome,oratthehospital;orperformingthetasks;theraterobservingortimingtheperformance;switchingtheimagingdeviceonandoff;positioningandmovingtheultrasoundprobe.

Dataprocessingandstorage

Allactionsundertakenontherawdatatostoreitinausable(electronic)formforlaterdatamanipulation(suchasscoreassignmentorstatisticalanalysis)

ThedigitallyconvertedsignalofaspecificbodyMRIscanwhichistemporarilystoredintheK‐space,issenttoanimageprocessorwhereamathematicalformula(i.e.Fouriertransformation)isapplied,leadingtoanimagewhichisdisplayedonamonitorandsavedonacomputer;Otherexamples:answersofquestionitemsarerecordedone.g.paperformsandstoredorLikertscaleformatresponseoptionsareconvertedintoa0‐4scoreanddirectlyenteredinacomputerdatabase.Performanceofdataqualitycheckse.g.doubleentryorvalidationchecksonthestored/entereddata.

Assignmentofthescore(s)

Methodsusedtoconvertprocesseddataintoascorecthatconstitutestheoutcomemeasurementinstrument.

Acalculationofamathematicalformulaortheapplicationofascoringsalgorithm(e.g.asetofrulestobefollowed)totheprocesseddata;aclinicianselectsthespecificimagesandjudgestheseverityandquantityofe.g.lesionsonthesetofimagesorcomparesittoareference;scoresadjustedfore.g.missingdataorpatientsusingdevicessuchasmobilityaids.

aProfessionalsarethosewhoareinvolvedinthepreparationortheperformanceofthemeasurement,inthedataprocessing,orintheassignmentofthescore;thismaybedonebyoneandthesameperson,orbydifferentpersons.bIntheCOSMINmethodologyweusetheword‘patient.’However,sometimesthetargetpopulationisnotpatients,bute.g.healthyindividuals,caregivers,clinicians,orbodystructures(e.g.joints,orlesions).Inthesecases,thewordpatientshouldbereadase.g.healthyvolunteer,clinician,ortherelevantbodystructure.cThescorecanbefurtherusedorinterpreted,byconvertingascoretoanotherscale,metricorclassification.Forexample,acontinuousscoreisclassifiedintoanordinalscore(e.g.mild/moderate/severe),ascoreisdichotomizedintobeloworaboveanormalvalue,patientsareclassifiedasrespondertotheintervention(e.g.whentheirchangeislargerthantheMinimalImportantChange(MIC)value).

Table3.Componentsofoutcomemeasurementinstrumentsthatinvolvebiologicalsampling

Equipment Allequipmentusedinthepreparation,theadministration,andthedeterminationofthevaluesoftheoutcomemeasurementinstrument

Collectiontools,suchasvenapunctureset,biopsytool;materialcontainers,suchasforbloodplasma(EDTAofheparintube),fortissue(containerforfrozenspecimensforimmunofluorescence,jarfilledwithformalin),forurinecollection(sterile,screw‐topcontainer),forstandardmicroscopictissueevaluation(fluidortissueforculture(sterilejar));laboratoryequipmentsuchascentrifuges,cabinets,andchromatographysystems,computers,software.

Preparatoryactionsprecedingsamplecollectionbyprofessionals,patients,andothers(ifapplicable)

1.Generalpreparatoryactions,suchasrequiredexpertiseortrainingforprofessionalstoprepare,administer,storeanddeterminethevalue

Training,educationorexperiencerequired,certification.

2.Specificpreparatoryactionsforeachmeasurement,suchas

preparationsofequipment,environment,andstoragebyprofessionalsa

preparationofthepatientbbytheprofessional

Preparationofequipment:calibrationofdevice/equipment,adjustsettingsofthemachine.Preparationoftheenvironment:lightconditions,roomtemperature,humidity.Preparationofstorage:set‐upallequipmentforstorage.Providegeneralandpreparatoryinstructionstothepatients,suchasexplainingthemeasurementprocedureincludingsafetyissuesandsideeffects;instructionsondiet;insertionandwithdrawalofacatheterintoabloodvessel.

Preparatoryactionsundertakenbythepatients

Listentoandunderstandingtheinstructionsprovided;adherencetothepreparatoryinstructionssuchasfasting,resting,takingmedication,exercising,shaving,washingofhands.

Collectionofbiologicalsample

Allactionsundertakentocollectthebiologicalsample,beforeanysampleprocessing

Takingabloodsampleortissuebiopsy,collectionofasampleofurine‘mid‐stream’inacontainer.

Biologicalsamplingprocessingandstorage

Allactionsundertakentobeabletopreserve,transport,andstorethebiologicalsamplefordetermination;and,ifapplicable,furtheractionsundertakenonthestoredsampletobeabletoconductthedeterminationofthebiologicalsample

Initialreactionofmaterialtoreagentincontainer(e.g.anticoagulationbyheparin).Bloodisdecomposed(bygravity)intoplasmaandbloodcells,andstoredataspecifictemperature.Tissueissnapfrozenbyimmersioninliquidnitrogen,orfixedinformalinembeddedin/processedtoparaffinforlong‐termstorage.Bloodiscollectedinatubecontaininganaqueoussolutiontetra‐sodiumsaltofethylene‐diamine‐tetra‐aceticacid(EDTA)andmixedwithairtolysetheerythrocytesandconverthemoglobintooxyhemoglobin.Cutsectionsorprepareasmearonaslide,tissuesarestainedbyimmunofluorescentmarkersspecificforcertainsurfaceantigens.Screwthelidoftheurinecontainershut,putinasealedplasticbagandstoreitinthefridgeataround4degreesCelsius,formax.24hours.

Determinationofthevalueofthebiologicalsample

Methodsusedforcountingorquantifyingtheamountofthesubstanceorentityofinterestc

Theabsorbanceofoxyhemoglobinat540nmthroughspectrophotometryquantifiesthehemoglobinconcentrationinthesample.Thepresenceofthemarkeronthecellsurfaceisdetectedandquantifiedbyfluorescencesignalintensity.Raterobserveseachslideandcountspositivecellsinanarea.Acalculationortheapplicationofamathematicalformulatothepreparedsample.

aProfessionalsarethosewhoareinvolvedinthepreparationortheperformanceofthemeasurement,inthedataprocessing,orintheassignmentofthescore;thismaybedonebyoneandthesameperson,orbydifferentpersons;bIntheCOSMINmethodologyweusetheword‘patient.’However,sometimesthetargetpopulationisnotpatients,bute.g.healthyindividuals,caregivers,clinicians,orbodystructures(e.g.joints,orlesions).Inthesecases,thewordpatientshouldbereadase.g.healthyvolunteer,clinician,orrelevantbodystructure;cThevaluecanbefurtherprocessedintoaclinicalscore,ifapplicable,byalinearorsemi‐quantitativeconversion.Forexample,acontinuousscoreisclassifiedintoanordinalscore(e.g.mild/moderate/severe),ascoresisdichotomizedintobeloworaboveanormalvalue,patientsareclassifiedasresponderontreatment(e.g.whentheirchangeislargerthantheMinimalImportantChange(MIC)value).Asnonoisewilloccurfromthisconversion,thisisnotapotentialsourceofvariance,butratheraninterpretationofthevalue.Thereforewedonotincludethisphaseinthecomponentsforoutcomemeasurementinstrumentsthatinvolvebiologicalmaterials.

2.2ExtractingtheelementsofacomprehensiveresearchquestionBeforewecancomprehensivelyassesstheinformationinastudyonthereliabilityormeasurementerrorofaninstrument,weneedtofullyunderstandthedesignofthestudyandreformulatetheresearchquestionintowhatwecalla‘comprehensiveresearchquestion’.Oftenthepublishedresearchquestionisnotspecificenoughtoratetheadequacyofthestudydesign.Forexample,ifthestatedaimoftheirstudyistoassessinter‐raterreliabilityofaninstrument,itisclearthatraterswillbevaried.However,withoutfurtherinformationitisnotclearwhethertheinterestisintheinter‐raterreliabilityofthewholemeasurementprocedure(e.g.bydifferentclinicians),oronlyinthereliabilityofapartofthemeasurementprocedure(e.g.onlytheassignmentofthescorebasedonanimage).Togetacompletepicture,werecommendtoextractsevenelementsfromthepublicationthattogethercanformthe‘comprehensiveresearchquestion’(seeTable4).Notethatonearticlecancontainmultiplequestions,eachrequiringanextractionofthesevenelements.Table4.Elementsofacomprehensiveresearchquestion.1 thenameoftheoutcomemeasurementinstrument2 theversionoftheoutcomemeasurementinstrumentorwayofoperationalizationofthe

measurementprotocol3 theconstructmeasuredbythemeasurementinstrument4 aspecificationwhetheroneisinterestedinareliabilityparameter(i.e.arelative

parametersuchasforcontinuousoutcomesanICC,Generalizabilitycoefficientφ,orKappaκ)oraparameterofmeasurementerror(i.e.anabsoluteparameterexpressedintheunitofmeasuremente.g.SEM,LoAorSDC;orforcategoricaloutcomesexpressedasagreementormisclassification,e.g.thepercentagespecificagreement).

5 aspecificationofthecomponentsofthemeasurementinstrumentthatwillberepeated(especiallywhenonlypartofthemeasurementinstrumentisrepeated,e.g.onlyassignmentofthescorebasedonthesameimages)

6 aspecificationofthesource(s)ofvariationthatwillbevaried(e.g.timeoroccasion,the(levelofexpertiseof)professionals,themachines,orothercomponentsofthemeasurement)

7 aspecificationofthepatientpopulationstudiedICC=Intraclasscorrelationcoefficient;SEM=standarderrorofmeasurement;LoA=LimitsofAgreement;SDC=smallestdetectablechange.

ElaborationontheelementsofacomprehensiveresearchquestionElement1.ThenameoftheoutcomemeasurementinstrumentThenameoftheinstrumentshouldbeexactlyspecified.Sometimes,thisisreadilyapparent,e.g.the6minuteWalkingtest(6MWT)ortheNineHolePegTest(NHPT).Insomecases,ameasurementprotocolinvolvesmultiplemeasurementinstruments(e.g.theMultipleSclerosisFunctionalComposite(MSFC)includestheTimed25‐FootWalktest,theNineHolePegTest,andthePacedAuditorySerialAdditionTest(11)),whileinothercases(e.g.imaging)theremaynotyetbeaclearname.Notethatthenameofthemachineisnotthenameoftheoutcomemeasurementinstrument;oftenamachinecanbeusedtomeasureavarietyofparameters(e.g.Greyscaleultrasound[tomeasure]synovialthickening(synovialhypertrophy)orDopplerultrasound[tomeasure]increasedbloodflow(Synovialhyperemia)(19)),orapathologicalentitycanbemeasuredbydifferenttypesofimages(forexample,enthesitismeasuredbyultrasound(17)orbyMRI(20)).Werecommendtoincludethetypeofmeasurement(e.g.ultrasound)incombinationwiththeentitymeasuredasthenameofthescore(e.g.ultrasoundenthesitisscore).Element2.TheversionoftheoutcomemeasurementinstrumentorwayofoperationalizationofthemeasurementprotocolDetailsontheversion,andoperationalizationoftheoutcomemeasurementinstrumentshouldbeextracted.Detailsonspecificversionreferthee.g.thelengthofthetask(e.g.the2‐,6‐or12‐minutewalkingtest(21)),orthenumberofitemsincludedintheversion(e.g.Doloplus‐1orDoloplus‐2(13)),orthelanguageused(theEnglish(21)orDutchversion(22)ofthe6‐minutewalktest).Choicesinhowthemeasurementprotocolwasoperationalizedmayaffectthemeasurement,andshouldthusbemadeexplicit.Specifically,thecomponentsthatarepotentialsourcesofvariation,needtobelisted,forexample,specificcharacteristicsoftheequipmentused(e.g.brandandtypeofthemachine),andcharacteristicsoftheprofessionalsinvolvedinthemeasurement(e.g.backgroundandexperiences).Thetaxonomyofthecomponentsofmeasurementinstruments(seechapter2.1)canbeusedforthis.Element2referstocomponentsknownorexpectedtoinfluencethescorethatarenottheobjectofstudy.Toeliminatetheinfluenceofthesepotentialsourcesofvariationonthescoresobtained,thesecomponentsshouldhavebeenrestrictedorstandardizedinthestudy.Forexample,ifitisexpectedthatdifferenttypesorbrandsofmachinesmayinterferewiththescore,onlyonetypeandbrandofamachineisused(andreported).InthestudybySkeieetal(2015)onlytheMedisonAccuvixV10ultrasoundscannerwitha3–7MHzcurvilinearprobewasused(19)–inotherwords,thebrandandtypeofmachineandprobewasstandardized.Moreover,chiropractorswithrespectively4and8yearsofexperiencedindiagnosticultrasoundforthemusculoskeletalsystem,andwitha

postgraduatediplomaindiagnosticultrasoundwereinvolvedinthemeasurements(19).Thus,thebackgroundoftheraterswasrestrictedtoaspecificprofession(i.e.chiropractors)withspecificdurationofexpertise(4/8yearsindiagnosticultrasound)havingreceivedspecifictraining.Inaddition,insomecasestheinstrumentprocedurerequiresmultiplereadings,andasummarystatistic(usuallythemean,butsometimesthemedian,maximumorminimum)iscalculatedasorusedtoassignthefinalscore(i.e.theresultsofthemeasurement).Awell‐knownexampleisbloodpressuremeasurementintheclinic.1Howthemeasurementistaken,shouldbespecified,asitisneededtoassessstandards7(seechapter3).ForpeoplefamiliarwiththeterminologyoftheGeneralizabilityTheory,theversionorthewayofoperationalizationofthemeasurementinstrumentreferstothefacetsofstratification,wherepatients(i.e.theobjectofmeasurement)arenestedinafacet(23).

Element3.TheconstructmeasuredbythemeasurementinstrumentToidentifyexactlywhichoutcomemeasurementinstrumentwasstudied,werecommendtoextracttheconstructmeasured,unlessitisclearfromthegivenname.Theconstructreferstowhatisbeingmeasured,i.e.the‘aspectofhealth’.Itisalsoreferredtoasthe‘conceptofinterest’orthe’intendedobjectivetobemeasured’.Whenthemeasurementinstrumentdoesnothaveaname,identifyingtheconstructcanhelptofullycharacterizetheoutcomemeasurementinstrument(whichwealsorecommendtomentioninthename,i.e.element1).Table5providessomeexamples.Notethatastudyonreliabilityormeasurementerrordoesnotprovideinformationaboutwhetherindeedtheconstructisbeingmeasured,forthatyouneedvalidityandaccuracystudies.

1 To measure blood pressure, the technician first palpates the radial artery, inflates the cuff until the pulse disappears, inflates an extra 20-30 mm Hg, and then slowly deflates until the pulse reappears. The pressure is noted, and the measurement begins: first, the stethoscope is placed on the brachial artery just medial and above the cubital fold. Then the cuff is reinflated. The pressure is quickly increased to 30 mm Hg above the previous reading, and then slowly deflated until the pulse sounds are detected (systolic blood pressure, measured in 2 mm increments), then further deflated until the sounds disappear (diastolic blood pressure). The cuff is fully deflated, then inflated again to repeat the measurement.

Table5.Examplesofelements1,2,and3.

Element 1: name Element2:version/operationalization Element3:construct

Nineholepegtest(24)

Awoodenorplasticboardwith9holes(10mmdiameter,15mmdepth),placedapartby32mm(25)

Fingerdexterity

Ultrasound enthesitis score

Sonography images obtained by experienced sonographers using the Esaote Technos MPX machine

Enthesitis

HbA1cvaluebasedonimmune‐turbidimetry(12)

Turbidimetricinhibitionimmunoassay(TINIA),including2reagens(i.e.anti‐HbA1cantibody(R1),andbuffer/polyhaptenreagent(R2));Tetradecyltrimethylammoniumbromide(TTAB)isdetergent;Roche/Hitachicobascsystems.

HbA1c(glycatedhaemoglobin)

Element4.Specificationofthemeasurementpropertyofinterest

Whenthemeasurementpropertyofinterestisreliability,thestudywillreportrelativeparameterssuchasanICC,Generalizabilitycoefficientφ,orKappaκ.Whenthemeasurementpropertyofinterestismeasurementerror,thestudywillreportabsoluteparameters,eitherexpressedintheunitofmeasurement,suchasSEM,LOAorSDC,orexpressedasagreementormisclassification,e.g.thepercentagespecificagreement.

WerecommendtousetheCOSMINterminologytodeterminewhetherastudyassessedreliabilityormeasurementerror,regardlessofthetermsusedinthearticle,becauseconfusionpersistsaboutthecorrectapplicationoftheseterms.Forexample,wheninaparticulararticleitisstatedthat‘reliability’wasassessed,butthestandarderrorofmeasurement(SEM)orthelimitsofagreementarereported,theresultofthatstudyshouldbeconsideredasevidenceformeasurementerror(26).Whenanauthorstatestohaveevaluated‘agreementbetweenraters’usingthekappastatistic,theresultofthisstudyreferstothereliabilityoftheoutcomemeasurementinstrument(27).

Element5.Specificationofthecomponentsofthemeasurementinstrumentthatwillberepeated.(Figure1)

Itshouldbeextractedwhethertheinterestofthestudyisinthereliabilityormeasurementerrorofthewholemeasurementprocedure(seeFigure1,studyA),oronlyinpartofthemeasurementprocedure(seeFigure1,studyB).Forexample,basedonanstaticimagethatwasmadeonceforapatient,onlytheassignmentofthescorewasrepeated,ortheperformanceofataskofeachpatientwasvideotaped,andonlythelastcomponent(i.e.assignmentofthescores)isrepeated.

Figure1.Whichpartofthemeasurementisrepeated.

Element6.Specificationofthecomponentsofthemeasurementinstrumentthatwillbevaried

Thecomponentofthemeasurementinstrumentthatisbeingvariedacrossthemeasurementsisthemainfocusofthestudy.Examplesaretimeoroccasion(test‐retest,orintra‐rater),theprofessionals(inter‐rater),orthemachines(inter‐machineorinter‐device)(28).Forexample,inFigure1ratersarevaried:raterAconductsthefirstmeasurementandraterBconductsthesecondmeasurementforeachpatients.

Inthedesignofthestudyoneormoresourcescanbeconsidered.Forexample,boththemachineandtheraterwhoconductsthewholemeasurementarevariedacrosstherepeatedmeasurements(seeFigure2,studyA).Thetaxonomiesofcomponentsofmeasurementinstruments(seechapter2.1)canbeusedtoconsidervariouspotentialsourcesofvariation.

Figure2.Designsinwhichcomponentsarevariedacrossrepeatedmeasurements

Alternatively,theresearcherscanassumethatacomponent(e.g.preparationorassignmentofthescore)is‘stable’,inotherwords,thattheraterwhopreparesthemeasurementorwhoassignsthescorewillnotintroduceerrorinthispartofthemeasurement(indicatedingreyinFigure2studyBandC),andinvestigateonlytheinfluenceofthecomponents(e.g.)equipment,preparation,collectionofrawdataanddataprocessingandstorage.

InthedesignsshowninFigure1and2weassumethatallpatientsweremeasuredthisway.Thisiscalledacrosseddesign(29).However,so‐callednesteddesignsarepossible,too(seeFigure3).Inthesedesigns,partofthepatientsaremeasuredfollowingmeasurementconditionsAandotherpatientsaremeasuredusingmeasurementconditionsB.InFigure3anestedinter‐raterreliabilitydesignisshown,wheresomeofthepatientsaremeasuredfirstbyraterAandnextbyraterB(i.e.measurementconditionA),whileotherpatientsaremeasuredfirstbyRaterCandnextbyraterD(i.e.measurementconditionB),etc.Thesedesignsareappropriatetouse,andinthecalculationoftheICC,thiscouldbetakenintoaccount.Forexample,bycalculating

variancecomponentspermeasurementcondition,andnextpoolthesevariancecomponents(weightedbysamplesize)acrossthemeasurementconditions(e.g.(30)),orbyusingaone‐wayrandomeffectsmodel(31).

Figure3.Nestedinter‐raterreliabilitydesign.

ForpeoplefamiliarwiththeterminologyoftheGeneralizabilityTheory,thecomponentsthatarebeingvariedacrossmeasurementsarecalledtherandomorfixedfacetsofGeneralizability(23).

Element7.Patientpopulation

Thereliabilitydependsonthehomogeneityorheterogeneityofthestudypopulation.Therefore,thesample(anditssubgroups)includedinthestudyshouldbeextractedandassessedbytheuserofthistool.InthestudybySkeieetal(2015)therecruitedsampleconsistedoflowbackpatients,patientswithotherspinalcomplaints,butalsoofpain‐freesubjects.Thislattergroupcouldhaveincreasedthevariancebetweenpatients,andsubsequently,influencedtheresults(i.e.increasedtheICC)ofthereliabilitystudy.

IntheCOSMINmethodologyweusethewordpatient.However,sometimesthestudypopulationofinterestconsistsofhealthyindividuals,bodystructures(e.g.joints,kidneys),cliniciansorcaregivers.Inthesecases,thewordpatientshouldbereadase.g.healthypersonorcaregiver.

ForpeoplefamiliarwiththeterminologyoftheGeneralizabilityTheory,thepatientpopulationreferstotheobjectofmeasurementorthefacetsofdifferentiation(23).

2.3ExampleofhowtousePartAoftheCOSMINRiskofBiastooltoassessthequalityofastudybySkeieetal.(2015)

InthischapterweprovideanexampleofhowtousetheCOSMINtool–PartAusingapaperbySkeieetal.(19).Togetafullunderstandingofthestudy,werecommendtofirstreadtheintroductionandmethodsectionofthepaper.Inthispaperfourdifferentstudiesaredescribed.Hereweusethefirsttwosubstudies,andprovideasummaryofthesetwostudies.

Inthispaper,thelumbarmultifidusmuscle(LMM)thicknessscore(study1)andcontractionscore(study2)wasinvestigatedbyultrasound.Themeasurementproceedsasfollows:apatientisaskedtolaydowninaspecificposition,andtheprobeisplacedonaveryspecificbodypart.Thisyieldsanon‐screenimage.Subsequently,amarkerisplacedonaspecificstructure(i.e.theapexofthefacetjoint)identifiedontheimage.Instudy1,astillimageisrecorded,andthefirstraterplacesthesecondmarkeronanotherspecificstructure(i.e.processusmammillaris)onthisimage,andmeasuresthedistancebetweenthemarkerswiththecallipersoftware.ThetwomarkerscorrespondwiththethicknessoftheLMM.Thefirstraterrepeatsthesecondmarkerplacementanddistancemeasurementonthestillimagetwice,foratotalofthreemeasurements.Thepatientleaves.Next,basedontheverysamestillimage(withonlythefirstmarkervisible)asecondraterplacesthesecondmarkeronthescreenandmeasuresthedistanceatotalofthreetimes.Next,alldataistransferredtoaseparatepaperbyrater1whocalculatesameanvalueperpatientperrater.ThismeanvalueistheLMMthicknessscore.Therepeatedplacementofthesecondmarkeronthestillimageandapplicationofthecalipertooltomeasurethedistancebetweenthetwomarkersispartofonemeasurement(19).ThisprocedureisdepictedinFigure3,study1.

Figure3.StudydesignsofSkeieetal.

Instudy2,foreachpatienteachoftheratersindependentlygeneratedoneimageoftheLMMintherestingstateandoneimageoftheLMMincontractedstate.Usingasplit‐screenofthetwostillimagesofbothstates,eachratermeasuredthickness(i.e.caliper‐assesseddistancebetweenthemarkers)ofthetwostatesthreetimes.Next,rater1transferredthedatatoaseparatepaperandcalculatedmeanvalues of the thickness of each state. Next,rater1calculatedthe‘LMMcontractionscore’astheexactchangeinthickness(contractedLMMminusrestingLMM)(19).ThisprocedureisdepictedinFigure3,study2.

BasedonthethoroughelaborationofthestudyperformedanddescribedbySkeieandcolleagues,weextracttheelementsofacomprehensiveresearchquestion.

Table6.ExampleofhowtousePartAoftheCOSMINRiskofBiastoolbasedonthestudybySkeie(19).

Element Instruction Study1 Study21.Nameoftheinstrument

Alternatively:typeofinstrumentandparameter

Ultrasoundmeasurementofthelumbarmultifidusmuscle(LMM)thicknessscore

UltrasoundmeasurementoftheLMMcontractionscore

2.Versionorwayofoperationalization

Allrelevantcomponentsthatareknownorexpectedtoinfluencethescore,andwhicharestandardizedorrestricted(facetofstratification(23))

Equipment:MedisonAccuvixV10ultrasoundscannerwitha3–7MHzcurvilinearprobe;Preparatoryactions:twochiropractorswith4respectively8yearsofexperienceindiagnosticultrasoundforthemusculoskeletalsystem,withapostgraduatediplomaindiagnosticultrasound;stillon‐screenimageswereobtainedwiththesubjectsinapronepositionwithapillowplacedundertheabdomentoflattenthelumbarlordosis.Preparation:Imagewason‐screengeneratedandamarkerwasplacedontheimageonthemamillaryprocessoftheleveltobemeasured.Unprocesseddatacollection:Thesecondmarkerwasplacedontheon‐screenimage,andthedistancewascomputedbythecallipersoftware.Thispartwasrepeatedthreetimes.

Preparation:Inrestingposition,animagewason‐screengeneratedandamarkerwasplacedontheimageonthemamillaryprocessoftheleveltobemeasured.Next,incontractedstate(LMMcontractionwasinducedbyacontralateralarmliftingtask),animagewason‐screengenerated,too,andamarkerwasplacedontheimage.

Element Instruction Study1 Study2Dataprocessingandstorage:Dataistransferredtoaseparatepaperbyrater1.

Unprocesseddatacollection:basedonthesplit‐screenofbothimages,thesecondmarkerwasplacesoneachimage,andthedistance(perimage)wascalculatedbythecallipersoftware.Thispartwasrepeatedthreetimes.Dataprocessingandstorage:Dataistransferredtoaseparatepaperbyrater1.

Assignmentofthescore:Rater1calculatedameanvalueperpatientperrater.

Assignmentofthescore:Rater1calculatesameanvalueperpatientperraterforbothstates.Next,theratercalculatedthe‘LMMcontractionscore’astheexactchangeinthickness(contractedLMMminusrestingLMM).

3.Construct Descriptionofwhatisbeingmeasured

LMMthickness LMMcontraction,whichischangeinLMMthicknessincontractedandrestingstate(contractedLMMminusrestingLMM).

4.Measurementproperty

Reliabilityandmeasurementerror

5.Componentsthatwillberepeated

Eitherthewholemeasurement(i.e.allcomponents)ortheassignmentofthescore(i.e.lastcomponent)

Thewholemeasurementwillberepeated.However,thefocusofinterestinontheunprocesseddatacollection:placingofthesecondmarkerontheon‐screenimage(meanofthreetimes).

Thewholemeasurementwillberepeated.However,thefocusofinterestinonthepreparation(i.e.preparationandgenerationofimagesintherestingandcontractedstates,andtheplacingofthefirstmarker),andontheunprocesseddatacollection(placingofthe

Element Instruction Study1 Study2secondmarkerontheon‐screenimage(meanofthreetimes).

6.Source(s)ofvariationvaried

Componentswhichisvariedacrossthemeasurements(i.e.focusofanalysis;facetofgeneralizability(23))

Raters(n=2;inter‐raterreliability)

7.Patientpopulation

(i.e.facetofdifferentiation(23))

LBPpatients,patientswithotherspinalcomplaintssuchasmidbackpain,neckpain,and/orextremitypain,andpain‐freesubjects(n=30ineachexperiment,totaln=120)

Basedontheextractedinformation,acomprehensiveresearchquestioncanbeformulatedas:

Study1:Whatistheinter‐raterreliabilityofthedatacollectionphaseofthelumbarmultifidusmuscle(LMM)thicknessscorebasedonthemeanofthreemarkeddistancewiththecallipersoftwareonastillimageoftheultrasoundmeasurement,measuredusingtheMedisonAccuvixV10ultrasoundscannerwitha3–7MHzcurvilinearprobebypost‐graduateexperiencedchiropractors,inLBPpatients,patientswithotherspinalcomplaintssuchasmidbackpain,neckpain,and/orextremitypain,andpain‐freesubjects?

Study2:Whatistheinter‐raterreliabilityofpreparing,generating,anddatacollectionphasesofthelumbarmultifidusmuscle(LMM)contractionscore,basedonthemeanofthreemarkeddistancewiththecallipersoftwareonanon‐screenimageinrestingandincontractionstateoftheultrasoundmeasurement,measuredusingtheMedisonAccuvixV10ultrasoundscannerwitha3–7MHzcurvilinearprobebypost‐graduateexperiencedchiropractors,inLBPpatients,patientswithotherspinalcomplaintssuchasmidbackpain,neckpain,and/orextremitypain,andpain‐freesubjects?

Please,notethatwedonotrecommendtoreporttheresearchquestionalwaysasthisinonelongquestion.Though,weconsideritveryusefultodescribeallthisinformationclearly,e.g.inthemethodsectionofapaper.

3. PartB.Assessingtheriskofbiasofastudyonreliabilityormeasurementerror

PartBoftheCOSMINRiskofBiastoolcontainstwoboxeswithstandardsthatcanbeusedtodeterminewhethertheresultofastudyonreliabilityormeasurementerror,respectively,canbetrusted.Standardsrefertothedesignrequirementsofthestudyortothepreferredstatisticalmethods.Thestandards1to5inbothboxesrefertodesignrequirements.Thesestandardsarethesameforstudiesonreliabilityandforstudiesonmeasurementerror,asthesamedesigncanbeusedforassessingbothmeasurementproperties.Threestandardsrefertothepreferredstatisticalmethodsforstudiesonreliabilityandtwostandardsrefertothepreferredstatisticalmethodsforstudiesonmeasurementerror.IntheCOSMINRiskofBiastool,weincludedstandardsconcerningthepreferredstatisticalmethodsthatareappropriatetousewhenevaluatingreliabilityormeasurementerrorofoutcomemeasurementinstruments(seealsosection1.6).Othermethodsmaybeappropriatetouseaswell(forexamplebi‐factormodelsorMulti‐TraitMulti‐Method(MTMM)analyses,ornewlydevelopedmethods).Itisnotourintentiontocomprehensivelydescribeallpossiblestatisticalmethods,rathertodescribetheadequatemethodsthatarecommonlyusedintheliterature.Eachboxalsocontainsastandardaskingiftherewereanyotherimportantmethodologicalflawsthatarenotcoveredbytheotherstandards(standard6),butthatmayhaveledtobiasedresultsorconclusions.Someflawsareratheruncommon,andtherefore,donotjustifyaseparatestandard.Inchapter3.1weprovideseveralexamplesfortheseflaws.Eachstandardwillbescoredonafour‐pointratingsystem(i.e.‘verygood’,‘adequate’,‘doubtful’,or‘inadequate’)inlinewiththeCOSMINRiskofBiaschecklistforPatient‐ReportedOutcomeMeasures(PROMs)(1).Subsequently,thelowestratinggiveninaboxdeterminesthefinalrating,i.e.thequalityofthestudy(thisiscalledtheworst‐score‐countsmethod(18)todeterminetheriskofbias).Sometimesaresponseoptionisindicatedingrey,meaningthattheresponseoptionisnotapplicableforthestandard,andusersshouldchoosebetweentheotheroptions.Final,somestandardscanberatedas‘notapplicable’.Ingeneral,astandardonadesignrequirementisratedas‘verygood’whenthereisevidenceorconvincingargumentswereprovidedthatthestandardismet;‘adequate’whenitisassumable,althoughnotexplicitlydescribed,thatthestandardismet;‘doubtful’whenitisunclearthatthestandardismet;and‘inadequate’whenthereisevidencethatthestandardisnotmet(18).Astandardaboutpreferredstatisticalmethodsisingeneralratedas‘verygood’whenapreferredmethodwasoptimallyused;‘adequate’whenthepreferredmethodwasused,

butitwasnotoptimallyused,‘doubtful’whenitisunclearifapreferredmethodwasused,and‘inadequate’whenthestatisticalmethodsusedareconsideredinadequate.Theboxesforreliabilityandmeasurementerror,respectively,canbefoundhere.Below,anelaborationofeachstandardisdescribedforreliability(chapter3.1)andmeasurementerror(chapter3.2).Inchapter3.3weprovideanexampleforratingtheboxonreliabilityinthestudybySkeie,thatwasalsousedasanexampleinchapter2.3.

3.1ElaborationonstandardsforstudiesonreliabilityTheboxonreliabilitycontainsfivestandardsaboutdesignrequirements,onestandards‘otherflaws’andthreestandardsaboutpreferredstatisticalmethods.Foreachstandardwegivesuggestionsforhowtoratethestandard.Standard1.Stabilityofthepatient verygood adequate doubtful inadequate NA

Werepatientsstableinthetimebetweentherepeatedmeasurementsontheconstructtobemeasured?

Yes(evidenceprovided)

Reasonstoassumestandardwasmet

Unclear No(evidenceprovided)

Notapplicable

Elaboration:Patientsshouldbestablewithregardtotheconstructtobemeasuredbetweentherepeatedmeasurements.Whenaninterventionsuchassurgeryormedicationisgivenintheinterimperiod,itislikelythat(manyof)thepatientshavechangedontheconstructtobemeasured.Inotherwords,theyarenotstable–andthestandardshouldberatedas‘inadequate’.Whentheaimistoassessthereliabilityoftheassignmentofthescore,e.g.usingstaticimagesorvideosoftheperformanceofataskasobjectofinterest(seeFigure1study2–page24),thisstandardisnotapplicableastheimagesandvideoswereacquiredonlyonce.Furthermore,themeasurementcaninterferewiththestabilityofthepatient.Forexample,thereshouldbeenoughtimeforpatientstorecoverfromexperiencedpainorfatiguebetweenrepeatedmeasurementsandpermitpatientstoreturntotheirinitialstate.Ifnot,thestandardshouldberatedas‘doubtful’,asitisunclearwhetherthepatientsarestableontheconstructtobemeasured.Whenevidenceorconvincingargumentsareprovidedthatthepatientswerestable,thestandardisscored‘verygood’.Standard2:Timeinterval verygood adequate doubtful inadequate

Wasthetimeintervalbetweenthemeasurementsappropriate?

Yes Doubtful,ORtimeintervalnotstated

Elaboration:Thetimeintervalbetweenthemeasurementsmustbeappropriate.Thedefinitionof“appropriate”dependsontheconstructtobemeasuredandthestudypopulation.Thetimeintervalshouldbelongenoughtopreventrecallbiasofpreviousscoresincaseofintra‐raterreliability,andshortenoughtoensurethatpatientshavenotchangedontheconstructtobemeasured.Forexamplesynovitiscanchangeinafewdays,whileachangeincartilageorbonestatuswouldtakeafewmonths.

Standard3.Similarmeasurementconditions

verygood adequate doubtful inadequate

Werethemeasurementconditionssimilarforthemeasurements–exceptfortheconditionbeingevaluatedasasourceofvariation?

Reasonstoassumestandardwasmet,ORchangewasunavoidable

Elaboration:Eachrepeatedmeasurementshouldbeconductedwiththesamemeasurementprotocol–exceptforthesourceofvariationthatwasintentionallyvaried,i.e.element6ofthecomprehensiveresearchquestion(seechapter2.2).Forexample,iftheaimwastounderstandthevariationduetodifferentraters(i.e.inter‐raterreliability),onlytheratersshouldbevaried.Otherconcomitantsourcesofvariation(i.e.element2ofthecomprehensiveresearchquestion,seechapter2.2)shouldbekeptsimilar.Wasthestudyuptostandard?Wereallequipment,preparatoryactions,theenvironmentalconditions(e.g.temperature),andmethodsofprocessingthesameinbothmeasurements?Forexample,whenthepatientsareverylikelytoshowalearningeffect(forexampleonaperformance‐basedtest),theabsenceofafamiliarizationsessionshouldyieldaratingofdoubtfulorinadequateonthisstandard,asthefirstmeasurementcanthenbeconsideredtobethefamiliarizationsession,andthemeasurementconditionsarenotthesame.Adescriptionofsimilarityofthemeasurementconditionsoftherepeatedmeasurementscanbeconsideredasevidence.Standards4.AdministrationofmeasurementsIninstrumentsthatdonotinvolvebiologicalsampling,theadministrationreferstothecomponents‘Collectionofrawdata’and‘Dataprocessingandstorage’(seechapter2.1).Ininstrumentsinvolvingbiologicalsampling,itreferstothecomponents‘Collectionofbiologicalsampling’and‘Biologicalsamplingprocessingandstorage’(seechapter2.1). verygood adequate doubtful inadequate

Didtheprofessional(s)administerthemeasurementwithoutknowledgeofscoresorvaluesofotherrepeatedmeasurement(s)inthesamepatients?

Elaboration:Allmeasurementsshouldbeadministeredbytheprofessional(s)involvedwithoutthemhavingknowledgeofthescoresorvaluesofotherrepeatedmeasurementsonthesameoutcomemeasurementinstrument.Thismeansthatthemeasurementsshouldallbeadministeredwithoutknowledgeoftheprior(e.g.incaseofanintra‐raterreliabilitystudy)orother(e.g.incaseofaninter‐raterreliabilitystudy)score(s)orvalue(s)ontheinstrumentofinterest.

Theratingofthisstandardisrathersubjective.Forexample,ifinastudytheratersindependentlyadministeredthemeasurement,andnonewereinvolvedinthecareofthepatients(makingitveryunlikelythattheratersreceivedadditionalinformationofthepatientsincludingknowledgeofthescore(s)ofotherrepeatedmeasurements),thiscanbeconsideredas‘evidenceprovided’,andtheratingis‘verygood’.Whentheotherscoreisknowntotheprofessionalwhileadministeringtherepeatedmeasurement,itmayinfluencethewaythemeasurementisadministered.Forexample,withaseverescoreobtainedwithanimagingtechnique,therepeatedmeasurementcanbeadministeredmorecarefully,andmoretimecanbeusedtolookatthepatient.Ifitisknownthatthiswasthecase,theratingis‘inadequate’.Whenthereisnoexplicitdescription,butitseemsveryunlikelythattheratersknewthescoresorvaluesofotherrepeatedmeasurements,itcanberatedas‘adequate’,or‘doubtful’.Insomesituationsthisstandardisnotapplicable,i.e.whentheadministration(i.e.collectionoftherawmaterialorbiologicalsample,dataorsamplingprocessingandstorage)isnotrepeatedinthestudy,butonlytheassignmentofthescoreorthedeterminationofthevalue(seeforexampleschapter2.2element5ofthecomprehensiveresearchquestion,orFigure1study2).Standard5.Assignmentofthescoreordeterminationofthebiologicalvalue

Didtheprofessional(s)assignscoresordeterminevalueswithoutknowledgeofthescoresorvaluesofotherrepeatedmeasurement(s)inthesamepatients?

Elaboration:Thescoresonallmeasurementsshouldbeassignedorvaluesshouldbedeterminedbytheprofessional(s)involvedwithoutthemhavingknowledgeofthescoresorvaluesofotherrepeatedmeasurements.Thismeansthatassigningascoretoameasurementordeterminingthevalueofabiologicalsampleshouldbedonewithoutknowledgeoftheprior(e.g.incaseofanintra‐raterreliabilitystudy)orother(e.g.incaseofaninter‐raterreliabilitystudy)score(s)orvalue(s)ontheinstrumentofinterest.Althoughpartofthedeterminationofthevalueofabiologicalsamplecanbeanautomaticstep,theremaybehumanactionrequiredtodothisdetermination.Forexample,anurinepHleveltesttomeasuretheacidityoralkalinityofurinewherethecolorofthestripisinterpretedbytheprofessional.Theratingissimilarlyasexplainedforstandard4.

Standard6.Otherimportantflaws verygood adequate doubtful inadequate

Werethereanyotherimportantflawsinthedesignorstatisticalmethodsofthestudy?

No Minorothermethodologicalflaws

Elaboration:Thisstandardisincludedbecausetheremightbeuncommondesignflawsthatarenotcoveredbyotherstandardsbutthatmaycauseadditionalriskofbias.Below,someexamplesareprovided.Whenvariousprofessionalsareinvolvedinthemeasurementinstrument,andoneoftheprofessionalsistheattendingphysicianofthepatient,thisphysicianhas(much)moreinformationaboutthepatientthantheotherprofessionals.Insomesituations–dependingontheaimofthestudyandthespecificconstructtobemeasured–thiscouldbeconsideredaflawbecauseoftheinfluenceonthescoresobtained.InthepreviouschapterwesawintheexampleofSkeiethatpartofthesamplecomprisedhealthypatients,whereastheauthorswereultimatelyinterestedinthesemeasurementsinlowbackpainpatients(19).Asthiswillincreasethevariancebetweenpatients,anditwillincreasetheresultsofthestudy(i.e.theICCorGCoefficient).Dependingonwherethisstudysitsinthedevelopmentoftheinstrument,thiscouldbedeemedproper(whenthefullrangeofthescoresisnotyetknown)oranimportantflawwhenthepurposeistodeterminethereliabilityofmeasurementintheclinicalsettingoflowbackpain.AfinalexamplereferstotheuseoftheICCmodelforaveragescores.Althoughdiscussedunderstandard7forreliability,itmaybethattheICCforthemeanscoreofthemeasurementsisreported,whereasinclinicalpracticethesinglescoreisused.Dependingonthepurposeofthestudythiscanbeproper(whenthemeanscoreisgoingtobeusedinfutureresearch)oranimportantflawwhenthestudyisaimedatprovingreliabilityonclinicalpractice(wherethesinglescoreisused).

ItisuptotheuseroftheCOSMINRiskofBiastoolwhetheraflawisconsideredminor(andisratedas‘doubtful’)orimportant(andisratedas‘inadequate’).Thescoresoftheotherflawsareincludedintheoverallscore/ratingbasedontheworstscorecountsprinciple.

Standard7:Preferredstatisticalmethodsforcontinuousscores verygood adequate doubtful Inadequate

Forcontinuousscores:wasanintraclasscorrelationcoefficient(ICC)calculated?

ICCcalculated;themodelorformulawasdescribed,andmatchesthestudydesignandthedata

ICCcalculatedbutmodelorformulawasnotdescribedordoesnotoptimallymatchthestudydesignORPearsonorSpearmancorrelationcoefficientcalculatedWITHevidenceprovidedthatnosystematicdifferencebetweenmeasurementshasoccurred

PearsonorSpearmancorrelationcoefficientcalculatedWITHOUTevidenceprovidedthatnosystematicdifferencebetweenmeasurementshasoccurredORWITHevidenceprovidedthatsystematicdifferencebetweenmeasurementshasoccurred

Elaboration:Forcontinuousscorestheintraclasscorrelationcoefficient(ICC)ispreferredtoevaluatereliability.ICCsareafamilyofstatisticalparameters,includingGeneralizability(G)coefficients,andDecision(D)coefficients.Togeta“verygood”rating,theICCmodelusedinthereliabilitystudyshouldmatchthestudydesign(andtheaim)ofthestudythatisbeingassessed.Therefore,themodelorformulaoftheICCorGCoefficientusedshouldbedescribed.Itshouldbeclear,e.g.whetheracrossedornesteddesignwasused(seealsopage25/26),orwhetheraone‐wayrandomeffectsmodel,two‐orthree‐wayrandomormixedeffectsmodelwasused.Next,itshouldbecomparedtothestudydesignusingtheextractedinformationfromPartA,anddeterminedwhethertheICCorGCoefficientusedindeedmatchesthestudydesign.TheICCbasedonthetwo‐waymixedeffectsmodelofconsistency(31)(alsoreferredtoasICCmodel3.1(32)),andthePearsonorSpearmancorrelationcoefficientdonottakeasystematicdifferencebetweentherepeatedmeasurementsintoaccount,andarethereforeconsideredlessappropriate,asitcanleadtooverestimatingthereliability.Therefore,basedoninformationofasystematicdifferencebetweenthesourceofvariationconsidered(e.g.raters)either‘adequate’(whennoorverylittlesystematicdifferenceoccurred),or‘doubtful’(whentherewasasystematicdifferencebetweene.g.theraters)canberated.Whenthestudywasdesignedtoinvestigateaspecificsourceofvariation(e.g.inter‐rater),andthesystematicdifferencesbetweenthissourceofvariationintherepeatedmeasurementswastakenintoaccountintheformula(forexample,byusingtheICCrandomeffectsmodelforagreement(31),alsoreferredtoasModel2.1(32)ortheφcoefficient(seee.g.(23)),thestudycanberatedas‘verygood’.Whenastudyisdesignedwithoutanyspecificsourceofvariationisconsidered,theappropriateICCmodelisaone‐wayrandomeffectsmodel(31).Inthissituationtheuse

ofaone‐wayrandomeffectsmodelcanberatedas‘verygood’,whiletheuseofothermodelscanberatedas‘adequate’.Next,theICCcanbecalculatedforasinglemeasurementoranaveragemeasurement(31).Ifasinglemeasurementisnormallyusedinclinicalpracticeortrials(andnottheaveragescoreofmultiplemeasurements,suchisdonebyabloodpressuremeasurement),theICCforsinglemeasuresshouldhavebeencalculated.TheICCaveragereferstothereliabilityoftheaveragedscoreofthemeasurements,andreferstotheuseoftheaveragedscoreonrepeatedmeasurements.WhentheICCforaveragemeasuresisreported,inthesituationthatusuallyasinglemeasurementistaken,werecommendthisstandardtoberatedas‘adequate’,asthemodeldoesnotoptimallymatchthedesignofthestudy.However,wealsorecommendinthissituation,toratestandard6(i.e.otherflaws),as‘doubtful’oreven‘inadequate’(seealsotheexampleatstandard6).Moreover,togeta‘verygood’rating,thedescribedICCorGcoefficientmodelorformulashouldmatchthedata.Ifthereisa(known)problemwithnormaldistributionofthedata(normality)whichisnotproperlytakenintoaccount,thestudycouldberatedas‘adequate’insteadof‘verygood’.Itisimpossibletodescribeallotherflawshere,ThereforeitisuptotheuseroftheCOSMINRiskofBiastooltodecidehowtheidentifiedflawshouldbescored.Relevantquestioninthisregardishowcertainandhowlargetheinfluenceisonthestudyresult.Standard8:Preferredstatisticalmethodsforordinalscores verygood adequate doubtful inadequate

Forordinalscores:wasa(weighted)kappacalculated?

Kappacalculated;theweightingschemewasdescribed,andmatchesthestudydesignandthedata

Kappacalculated,butweightingschemenotdescribedordoesnotoptimallymatchthestudydesign

Elaboration:Toassessreliabilityforordinalscores,Cohen’skappa(33‐35)isconsideredthepreferredstatisticalparameter.Nobetteralternativeisknown(4,36).Informationonthespecifickappausedshouldbedescribedintermsofwhetheraweightingschemewasusedandwhichschemewasused.Unweightedkappaconsidersanymisclassificationequallyinappropriate.However,amisclassificationoftwoadjacentcategoriesmaybelesserroneousasamisclassificationofcategoriesthataremoreapartfromeachother.Aweightedkappatakesthisintoaccount(e.g.usinglinearorquadraticweights(37)).Ifthegoalofthestudywastoconsideranymisclassificationasequallyimportant,anditwasstatedthattheunweightedkappawasused,thisstandardcanberateda‘verygood’.However,inothersituation(e.g.misclassificationofcategoriesmore

apartfromeachotherisabiggerproblemthatmisclassificationofadjacentcategories)aspecificweightingschemeismorepreferred.Ifunweightedkappacalculatedinthatcasethestandardcouldberatedas‘adequate’.Standard9:Preferredstatisticalmethodsfordichotomousornominalscores

Fordichotomous/nominalscores:wasKappacalculatedforeachcategoryagainsttheothercategoriescombined?

Kappacalculatedforeachcategoryagainsttheothercategoriescombined

Elaboration:Astudyonreliabilityofanoutcomemeasurementinstrumentwithdichotomousornominalscoresgetsa‘verygood’score,whenanunweightedkappawascalculatedofeachcategoryagainsttheothercategories(33).

3.2Elaborationonstandardsforstudiesonmeasurementerror

Standards1to6oftheboxforstandardsforstudiesonmeasurementerrorarethesameasforstudiesonreliability.Foranelaborationoneachofthestandards,pleaseseeabove.Standard7:Preferredstatisticalmethodsforcontinuousscores

Forcontinuousscores:wastheStandardErrorofMeasurement(SEM),SmallestDetectableChange(SDC),LimitsofAgreement(LoA)orCoefficientofVariation(CV)calculated?

SEM,SDC,LoAorCVcalculated;themodelorformulafortheSEM/SDCisdescribed;itmatchesthereviewerconstructedresearchquestionandthedata

SEM,SDC,LoAorCVcalculated,butthemodelorformulaisnotdescribedordoesnotoptimallymatchthereviewerconstructedresearchquestionandevidenceprovidedthatnosystematicdifferencehasoccurred

SEMconsistencySDCconsistencyorLoAorCVcalculated,withoutknowledgeaboutsystematicdifferenceorwithevidenceprovidedthatsystematicdifferencehasoccurred

SEMcalculatedbasedonCronbach’salpha,ORusingSDfromanotherpopulation

Elaboration:ForcontinuousscorespreferredmeasuresforthemeasurementerrorofasinglescorearetheSEM,LoAortheCoefficientofVariation(CV);theSDCispreferredasameasureforchangescores.Differentformulascanbeusedtocometocalculatethesevariousmeasures.Therefore,wewillfirstdescribetheirformulas.Subsequently,wewillexplainthestandardforstudiesusingSEMandSDCderivedfromvariancecomponentsanalyses.Next,wewilldiscussLoA,SEMandSDCusingtheSDdifference.Wewillexplainwhenignoringtheinfluenceofthesourceofvariationisappropriate.Andlast,wewilldiscusssomeothermethodsused,includingtheCV.Measuresthattakeallerrorintoaccount,includingthesystematicdifferencebetweenrepeatedmeasurements,basedonaone‐wayortwo‐wayeffectsmodel,are:

1.96 ∗ √2 ∗ 1.96 ∗ √2 ∗ (3)

Measuresthatdonottakethesystematicdifferencebetweenrepeatedmeasurementsintoaccount:

1.96 ∗ √2 ∗ 1.96 ∗ √2 ∗ (5)

1.96 ∗ √2 ∗ 1.96 ∗ √2 ∗√

1.96 ∗ (8)

1.96 ∗ (9)

Togeta‘verygood’rating,theformulausedshouldmatchthestudydesign(andtheaim)ofthestudythatisbeingassessed.Therefore,itshouldbeclearwhattheaimis,andwhichmeasureorwhichformulawasusedinthestudybeingassessed.Measurementerrorderivedfromvariancecomponentsanalyses(formulas1‐5)Thespecificmodelusedshouldbeclearlydescribed,e.g.whetheraone‐wayrandomeffectsmodel,oratwo‐orthree‐wayrandomormixedeffectsmodelwasused,andwhetherallerror(exceptfromthevarianceduetovariationbetweenpatients)wasincludedinthecalculationofthemeasurementerror,orwhetherthesystematicerrorbetweenthesourceofvariationthatisbeingvariedinthedesignisignored(i.e.asoccurredwhencalculatingSEMconsistencyforsinglescores(formula4)andSDCconsistencyforchangescores(formula5)).Next,itshouldbecomparedtothestudydesignusingtheextractedinformationaboutthecomprehensiveresearchquestion(seePartAofthetool),anddeterminedwhetherthemethodusedindeedmatchesthestudydesign.Inotherwords,whentheaimofthestudywastoassessthemeasurementerrorofasinglescoreofanymeasurementtakeninclinicalpracticeoftrials,theaimistogeneralizetheresultsbeyond(e.g.)thespecificratersinvolvedinthestudy.Inthiscase,thesystematicerrorbetweenratersshouldbetakenintoaccount;theraters(inthisexample)shouldbeconsideredrandom;andallerrorshouldbetakenintoaccount(i.e.formulas1‐3)tomatchthedesignofthestudy(andthisisrated‘verygood’).Ifinthiscase,(withtheaimtogeneralizebeyondthespecificraters)theSEMconsistency(formula4)orSDCconsistency(formula5)wascalculated(i.e.ignoringasystematic

differencebetweenraters),evidenceshouldbeprovidedthatno(oronlyverysmall)systematicdifferencehasoccurredbetweentheraters.Incaseofnoorverysmalldifferencesthestandardcanberatedas‘adequate’,astheSEMagreement(formula2)andSEMconsistency(formula4),orSDCagreement(formula3)andSDCconsistency(formula5)willbethesameorveryclose.Ifitisunclearwhethersystematicdifferencesoccurred(becauseitwasnotreported),thestandardisratedas‘doubtful’.MeasurementerrorderivedfromtheSDdifference(formulas6‐9)ThemeasurementerrorofasinglescoreorachangescorecanalsobecalculatedusingtheSDdifference.Thisreferstothestandarddeviationofthedifferenceofthescoresontherepeatedmeasurements(38,39).InaBlandandAltmanplottworepeatedmeasurementsperpatientareplotted:onthex‐axesthemeanscoreofthetwomeasurements,andonthey‐axesthemeandifferencebetweentherepeatedmeasurements(39).Althoughtheplotisdesignedinsuchawaythatsystematicdifferencescaneasilybeseen(i.e.thelineofthemeandifferencesinscores,andtheasymmetricallylocatedlimitsofagreementaroundthezero),thesystematicdifferenceisdisregardedwhentheSDCiscalculatedfromtheselimits(resultingintheSDCconsistency).Therefore,ifa(large)systematicerrorbetweentherepeatedmeasurementsoccurred,whiletheaimofthestudyistogeneralizebeyondthespecificsourceofvariation(e.g.raters),thestandardshouldberatedas‘doubtful’,astheresultsofthestudyisunderestimatingthemeasurementerror.Whenisameasureofconsistency(formulas4‐9)appropriate?Sometime,thesourceofvariationthatisbeingvariedacrossthemeasurementsisconsideredtobefixedinastudy.Thismeansthattheaimofthestudyisnottogeneralizebeyondthespecificstudyobjectsincludedinthestudy.Forexample,inastudyonlytworatersareconsidered(e.g.theratersMyrtheandBrechtje),andtheaimofthestudyiswhetherthesetworaterswillcometoequalscores(e.g.becausetheywillbetheonlytworatersinvolvedinthemeasurementsforaspecifictrial).IfasystematicerroroccursbetweenMyrtheandBrechtje(e.g.Myrthesystematicallyscores5pointshighercomparedtoBrechtje),thescoresobtainedinthetrialcaneasilybeadjustedbyextracting5pointsofeachmeasurementobtainedbyMyrthe.Inthisstudy,thesourceofvariation‘rater’isdeemedirrelevant(31),asthesystematicdifferencewillbeadjustedlateronwhenusingtheinstrumentbyeitherMyrtheorBrechtje.Inthisspecificsituation,theSEMconsistency,SDCconsistencyorthelimitsofagreementmatchtheaimanddesignofthestudy,soitcanberatedas‘verygood’.However,theseresultscannotbegeneralizedtootherraters,as‘rater’wasconsideredfixed.Therefore,thestudyislessrelevantinothersituations,especiallywhenthereisasystematicdifferencebetweentheraters.

MeasurementerrorcalculatedusingtheformulaSD*(√1‐ICC)ThereisanotherformulawhichissometimesusedtocalculatetheSEMfromtheICCformula:SEM=SD*(√1‐ICC)(40).ThestandarddeviationreferstotheSDpooledofthesample,thatisofSDtestandSDretest.UsingthisformulaisonlyjustifiedifthedataforICCandSDarederivedfromthesamestudy.WhentheSDisbasedonanotherpopulation,thisisconsideredinadequate,astheSDofthisotherpopulationmaybesmaller,andsubsequently,themeasurementerrorissmaller.Moreover,sometimestheCronbach’salphaisinsertedintheformulainsteadoftheICC.Thisisconsideredinadequate,asthismeasureisbasedononefull‐scalemeasurementwhereitemsareconsideredastherepeatedmeasurements,insteadofatleasttwofull‐scalemeasurementsusingthetotalscoreinthecalculationoftheSEM.OftenCronbach’salphaishigherthanICC’sbasedonrepeatedmeasurements,thusleadingtosmallerSEMvalues.Byratingthisinadequate,theresultofthisstudycanstillbeconsidered,however,itisconsideredtobelesstrustworthy.Moreover,Cronbach’salphaissometimesusedinadequately,becauseitiscalculatedforascalethatisnotunidimensional,orbasedonaformativemodel.InsuchcasestheCronbach’salphacannotbeinterpreted.Otherparametersthatarebasedonsinglemeasurements,suchasthepersonseparationindex(orotherIRT‐basedmeasurementerrormeasures)ortheOmega,arenotcoveredbythemeasurementerroraccordingtotheCOSMINtaxonomy,butbyinternalconsistency.TheCoefficientofvariationCoefficientofvariation(CV)isalsoaparameterofmeasurementerror.Itisoftenusedinphysicsandtopresentthemeasurementerrorofadevice.Whendevelopinganewdevicethemeasurementerrorisassessedbymeasuringafixedsamplemany(e.g.50)times.TheSDofthesemeasurementsisthestandarderrorofmeasurements.Oftenthemeasurementerrorincreaseswithhighervalues.ForthesesituationCVisasuitablemeasure,asCVexpressestheSDaspercentageofthemeanvalue:informulaCV=SD/mean.Usually,itisexpressedinpercentage,forexample,themeasurementerroris2%ofthemeasuredvalue.TheassumptionunderlyingCVisthattheCVgivesaconstantvalueoverallvaluesofthemean,sothattheSDise.g.2%ofthemeanvalue,regardlessofameanvalueof10or100or1000.InaBlandandAltmanplot,wehadacontraryassumption,i.e.thattheSDofthedifferenceisconstantoverthemeanvalues,ontheX‐axis.Ifthedifferencesarelowerwithsmallvaluesandhigherwithlargevaluethehorizontallinesofthelimitsofagreementgiveawrongvalue:toolargeforthesmallvaluesandtoosmallforthelargemeanvalues.Inthatcaseoneshouldtransformthedata.Oftenanaturallogarithmor10loglogarithmtransformationisused.Thishastheadvantagethatthelimitsofagreementcanbedirectlyexpressedinacoefficientsofvariation(41).

Standard8:Preferredstatisticalmethodsfordichotomous,nominal,orordinalscores

Fordichotomous/nominal/ordinalscores:Wasthepercentagespecific(e.g.positiveandnegative)agreementcalculated?

%specificagreementcalculated

%agreementcalculated

Elaboration:Oftenkappaisconsideredasameasureofagreement,however,kappaisameasureofreliability(42).Anappropriateparameterofmeasurementerror(alsocalledagreement)ofdichotomous/nominal/ordinalscoresistheproportionofspecificagreement(42‐44).Itisameasurethatexpressestheagreementseparatelyforeachcategoryofthescore–thatispositiveandnegativeratingsagreementincasethescoreisdichotomous.

3.3ExampleofhowtousePartBoftheCOSMINRiskofBiastooltoassessthequalityofastudybySkeieetal.(2015)

InthischapterweprovideanexampleofhowtousetheCOSMINtool–PartBusingagainthepaperbySkeieetal.(19).TofullyunderstandtheexplanationinTable7,werecommendtofirstreadtheintroductionandmethodsectionofthepaper,andthesummaryprovidedatpage27/28.Inthispaperfourdifferentstudiesaredescribed.Hereweusethefirsttwosubstudies.

Table7.ExampleofhowtousePartBoftheCOSMINRiskofBiastoolbasedonthestudybySkeie(19).

StandardsondesignrequirementsforReliabilityandMeasurementerrorDesignrequirements Ratingstudy1 Ratingstudy2 1 Werepatientsstableinthetimebetween

therepeatedmeasurementsontheconstructtobemeasured?

NA(measurementswerebasedonastillimage

Verygood.Measurementswereconductedinsuccession.

2 Wasthetimeintervalbetweentherepeatedmeasurementsappropriate?

NA Verygood.Thetimeinterval(i.e.thesecondraterstartedimmediatelyafterthefirsthadcompletedtheprocedure)hasprobablynotinfluencedthescores.

3 Werethemeasurementconditionsimilarfortherepeatedmeasurements–exceptfortheconditionbeingevaluatedasasourceofvariation?

Verygood Verygood

4 Didtheprofessional(s)administerthemeasurementwithoutknowledgeofscoresorvaluesofotherrepeatedmeasurement(s)inthesamepatients?

Verygood.Noneofthepreviousscoreswereavailable

5 Didtheprofessional(s)assignthescoresordeterminedthevalueswithoutknowledgeofthescoresorvaluesofotherrepeatedmeasurement(s)inthesamepatients?

Verygood.Noneofthepreviousscoreswereavailable

6 Werethereanyotherimportantflawsinthedesignorstatisticalmethodsofthestudy?

Forreliability:Doubtful.5of30persons(seeTable1ofthepaper)werepain‐freesubjects,whichcouldhavemajorlyincreasedthevariationbetweenthepatients,andsubsequentlytheICC

Forreliability:Verygood.(inthisstudynopain‐freepersonswereincluded,seeTable1ofthepaper)

Formeasurementerror:verygood.Heterogeneityofthesampleisconsideredlessaproblem,asthevariationbetweenpatientsisnotincludedintheparameter.

StandardsonpreferredstatisticalmethodsforReliability Ratingstudy1 Ratingstudy2

7 Forcontinuousscores:wasanIntraclass

CorrelationCoefficient(ICC)calculated?

Adequate.ICCtwo‐waymixedsinglemeasures(3.1)andtwo‐waymixedaveragemeasures(3.2)werecalculated.ThisistheICCconsistency,whichdoesnottakethesystematicerrorbetweenratersintoaccount.Thestudyaimstogeneralizebeyondtheratersinvolved,therefore,theratersshouldnotbeconsideredfixed,andtheICCmodeldoesnotmatchoptimallytheresearchaimanddesign.BasedonthemeanofthemeasurementsprovidedinTable2,wecanconcludethatnosystematicdifferencebetweentheratersoccurred.TheICCtwo‐waymixedaveragemeasures(3.2)referstothepracticeinwhichtworaterswouldmeasureeachpatient(withtripleplacementofsecondmarker),andbothfinalscoreswereaveraged.Asthiswillnotbecommonpractice,wewillignorethisICC.Therepetitionofpartofthemeasurementisalreadypartofonemeasurement.

8 Forordinalscores:wasa(weighted)

Kappacalculated?

Notapplicable Notapplicable

9 Fordichotomous/nominalscores:was

Kappacalculatedforeachcategoryagainst

theothercategoriescombined?

FinalRiskofBiasratingReliabilitystudies Doubtful Adequate

StandardsonpreferredstatisticalmethodsforMeasurementerrorRatingstudy1 Ratingstudy2

7 Forcontinuousscores:wastheStandard

ErrorofMeasurement(SEM),Smallest

DetectableChange(SDC),Limitsof

Agreement(LoA)orCoefficientofVariation

(CV)calculated?

Adequate,asthelimitsofagreementwerecalculated,whiletheaimwastogeneralizebeyondtheratersincludedinthisstudy,andprobablytherewasnosystematicdifferencebetweentheraters.

8 Fordichotomous/nominal/ordinalscores:

Wasthepercentagespecific(e.g.positiveand

negative)agreementcalculated?

FinalRiskofBiasratingstudyonMeasurement

Adequate Adequate

4. UsingtheCOSMINRiskofBiastoolinasystematicreviewofoutcomemeasurementinstruments

Researchersandclinicianswhoaredecidingonthemostsuitableoutcomemeasurementinstrumentforuseintheirstudy,canoftenchoosefrommultipledifferentinstruments.Theselectionshouldbebasedontheevidenceofthequalityoftheoutcomemeasurementinstruments(i.e.reliability,validity,andresponsiveness),aswellasonaspectsoffeasibilityandinterpretability.Ahigh‐qualitysystematicreviewonoutcomemeasurementinstrumentsgivesaclearoverviewofallimportantaspectstomakeyourchoice.Understandingthequalityofthestudiesandthequalityofthemeasurementinstrumentunderstudyisachallengingtask,specificallyforresearchersandclinicianswhoarelessfamiliarwiththemethodologytoevaluateallmeasurementproperties.Therefore,in2018,we(COSMINinitiative)publishedathoroughmethodologytoconductasystematicreviewofPROMs(5).Itconsistedofaten‐stepproceduretosummarizetheavailableevidencepermeasurementpropertyperincludedPROManddrawconclusionsoneachmeasurementpropertyperPROM.Andsubsequently,togiverecommendationsofthemostsuitablePROMforagivenpurpose,includingalsofeasibilityandinterpretabilityaspects.ThismethodologyalsoincludestheCOSMINRiskofBiaschecklisttoassessthequalityofstudiesonmeasurementpropertiesofPROMs(1),includingstandardsfordesignrequirementsandpreferredstatisticalmethodsorganizedinboxespermeasurementproperty.ToperformasystematicreviewonthequalityofClinROMs,PerFOMsandlaboratoryvalues,thesamemethodologycanbeused.However,werecommendsomeadaptations.TwoaspectsoftheCOSMINmethodologyforsystematicreviewsofPROMsaredifferentforClinROMs,PerFOMsorlaboratoryvalues:recommendationtousedifferentboxesforreliabilityandmeasurementerror,andtheadditionofanewstepThenewboxesInsystematicreviewsofClinROMs,PerFOMsorlaboratoryvaluestheCOSMINRiskofBiaschecklistforPROMs(1)canbeused,althoughtheboxesforreliabilityandmeasurementerrorshouldbereplacedwiththeCOSMINRiskofBiastooltoassessthequalityofastudyonreliabilityormeasurementerror(4).Standardsformostoftheremainingmeasurementproperties(i.e.contentvalidity,internalconsistency,constructvalidity,criterionvalidityandresponsiveness)developedforPROMscanbeusedforothertypesofmeasurementinstrumentsaswell.Somemeasurementpropertiesareonlyrelevantformulti‐iteminstrumentsbasedonareflectivemodel(i.e.structuralvalidityandinternalconsistency).Forsomeothermeasurementpropertiesonlythefinalscoreorvalueofameasurementinstrumentisconsidered(i.e.hypothesestesting

forconstructvalidity,criterionvalidityandresponsiveness).Thequalityofstudiesonthesemeasurementpropertiesaresimilarlyassessedforalltypesofoutcomemeasurementinstruments,andtheexistingboxesfromtheCOSMINRiskofBiaschecklistforPROMscanbeused.AnadditionalstepInareliabilitystudyorastudyonmeasurementerrorofaPROMthefocusofinterestisusuallyonthequalityofthePROMasitisbeingusedinclinicalpractice(analyzedusingaone‐wayrandomeffectsmodel),orinthetest‐retestreliability(usingatwo‐wayrandomeffectsmodelofagreement).However,thefocusofinterestinareliabilitystudyofothertypesofmeasurementinstrumentsismuchmorediverse.Asexplainedinchapter2,therearemanypotentialsourcesofvariation(i.e.manydifferentwaystooperationalizethecomponentsofoutcomemeasurementinstruments)thatcouldbethefocusofinterestinastudyonreliability.Eachresultofallthosestudiestellsyousomethingaboutthequalityoftheinstrument(andgivessuggestionsforimprovementofthemeasurementbystandardizingorrestrictingthesourceofvariationwhichshowedthelargesterror).Basedonanoverviewofallthesestudies,anbest‐evidencemeasurementprotocolcanberecommended.InaCOSMINreviewsofClinROMs,PerFOMsorlaboratoryvalues,anadditionalstepisneededintheten‐stepprocedure(seeFigure3),specificallyintheassessmentofreliabilityandmeasurementerror.Towellinterprettheresultsofstudiesincludedinasystematicreview,youneedtodecidehowtheresultsofthestudyyouwanttoassessinformyouaboutthequalityofthemeasurementinstrument.Therefore,weseparatedtheassessmentofreliabilityandmeasurementerrorfromtheothermeasurementproperties.Changeinthemethodology

Basedonourexperienceusingthemethodology,wedecidedtoremovestep8(whichwas‘Evaluateinterpretabilityandfeasibility’)fromthemethodology.Aspectsofinterpretabilityandfeasibilityareonlyextracted(andsummarized)ratherthanevaluated.Therefore,thisstepisirrelevantinthemethodology.However,weconsideritveryusefultohaveaseparatestepondataextraction.Onceyouincludedallthestudiesinareview,wefirstrecommendyoutoextractallnecessaryinformationfromanarticle,beforeassessingtheriskofbias,andthequalityoftheinstrument.Relevantinformationtobeextractedreferstocharacteristicsoftheincludedmeasurementinstruments,informationonfeasibilityandinterpretability,characteristicsofthestudies,andtheresultsofthestudy.

Consequently,thestep‐numbersaredeviatingfromthestepnumberspresentedintheoriginal10‐stepprocedureoftheCOSMINmethodologytoconductasystematicreviewofPROMs(5).

Figure3.Eleven‐stepprocedureforconductingasystematicreviewonanytypeofoutcomemeasurementinstrument

4.1Theeleven‐stepprocedureforconductingasystematicreviewofClinROMs,PerFOMs,orlaboratoryvalues

Below,asummaryisgivenfortheeleven‐stepprocedure.IntheusermanualoftheCOSMINmethodologyforsystematicreviewsofPROMs(45)athoroughexplanationofeachstepisprovided.OnlythestepsthataredifferentforareviewofoutcomemeasurementinstrumentsotherthanPROMsaredescribedhereindetail.Pleasenotethatthenumberofthesteparechanged.

Themethodologyofasystematicreviewofoutcomemeasurementinstrumentsissubdividedintothreeparts(A,B,andC)(5).

Step1‐4:Performtheliteraturesearch

Thesteps1‐4arestandardprocedureswhenperformingsystematicreviews,andareinagreementwithexistingguidelinesforreviews(46,47):formulatingthespecificaimofthereview,andtheeligibilitycriteria,performingtheliteraturesearch,andselectingrelevantpublications.

Intheresearchquestion,andeligibilitycriteriafourkeyelementsshouldbeincluded:1)theconstruct;2)thepopulation;3)thetype(s)ofinstruments;and4)themeasurementpropertiesofinterest.

Inthesearchstrategywerecommendtoalsousethesekeyelements,exceptfromthetypeofinstruments,aswearenotawareofhighlysensitivesearchblocksfordifferenttypesofmeasurementinstruments.Searchfiltersfordifferentconstructsmaybefoundathttps://blocks.bmi‐online.nl/.Whenusingthesearchfilterforfindingstudiesonmeasurementproperties(48)ofCLinROMs,PerFOMsandlaboratoryvalues,werecommendtouseadditionalsearchtermsforfindingstudiesusingGeneralizabilitytheory.Thisstring,developedwiththehelpofaclinicallibrarian,canbeaddedwiththebolean“OR”tothesearchfilter.

PubmedsearchstringforfindingstudiesusingGeneralizabilitytheory:

G‐theory[tiab]OR"Gtheory"[tiab]OR"generalizabilitytheory"[tiab]OR"generalisabilitytheory"[tiab]

EMBASEsearchstringforfindingstudiesusingGeneralizabilitytheory:

‘g‐theory’:ti:abOR‘gtheory’:ti,abOR‘generalizabilitytheory’:ti,abOR‘generalisabilitytheory’:ti,ab

Step5:Dataextraction

Onceyouincludedallrelevantarticles,youcheckperarticlewhichmeasurementpropertieswereevaluated(andsubsequentlydecidewhichCOSMINboxesarerelevanttobecompletedforthespecificarticle).Whenreadingthroughthearticle,atthispoint,werecommendyoutoextractallinformationfromthearticleaboutthecharacteristicsoftheincludedmeasurementinstruments(forsuggestionsofcharacteristicsseeappendix4),includingaspectsoffeasibilityandinterpretability(seebelow).Interpretabilityisdefinedasthedegreetowhichonecanassignqualitativemeaning(thatis,clinicalorcommonlyunderstoodconnotations)toaquantitativescoreorchangeinscoresofanoutcomemeasurementinstrument(7).Boththeinterpretabilityofsinglescoresandtheinterpretabilityofchangescoresisinformativetoreportinasystematicreview.Theinterpretationofsinglescorescanbeoutlinedbyprovidinginformationonthedistributionofscoresinthestudypopulationorotherrelevantsubgroups,asitmayrevealclusteringofscores,anditcanindicatefloorandceilingeffects.TheinterpretabilityofchangescorescanbeenhancedbyreportingM(C)ICvalues.However,thereisanongoingdebateabouthowthesevaluesshouldbeassessed.

Feasibilityisdefinedastheeaseofapplicationofthemeasurementinstrumentinitsintendedcontextofuse,givenconstraintssuchastimeormoney(49).Aspectsoffeasibilityare,forexample,completiontime,costofaninstrument,lengthoftheinstrument,typeandeaseofadministration.Feasibilityappliestoboththepatientsandtheprofessionalwhoareinvolvedinthemeasurement.Theconcept‘feasibility’isrelatedtotheconcept‘clinicalutility’,wherefeasibilityreferstoameasurementinstrument,andclinicalutilityreferstoanintervention(50).

Interpretabilityandfeasibilityarenotmeasurementpropertiesbecausetheydonotrefertothequalityofanoutcomemeasurementinstrument.However,theyareconsideredimportantaspectsforawell‐consideredselectionofanoutcomemeasurementinstrument.

Steps6‐9:Evaluatethemeasurementproperties

Thesteps6‐9concerntheevaluationoftheninemeasurementpropertiesoftheincludedoutcomemeasurementinstruments.Inthesestepspermeasurementproperty,dataisextractedonthecharacteristicsofthestudies,andtheresultofeachstudy,theriskofbiasoftheincludedstudiesisratedbyusingtheCOSMINRiskofBiasstandards,andtheresultsofthestudiesareratedbyapplyingthecriteriaforgoodmeasurementproperties.Subsequently,allevidenceissummarized,andthequalityofallavailableevidencepermeasurementpropertypermeasurementinstrumentisgradedusingamodifiedGRADEapproach.

Characteristicsofthestudiesrefertothecharacteristicsoftheincludedpatientpopulations,andpopulationofincludedprofessionals(forsuggestionsofcharacteristicsseeappendix5).Forspecificrecommendationsforextractinginformationontheresultsofstudiesonreliabilityandmeasurementerrorseestep8extractinginformation(p53).

Instep6thecontentvalidityisassessed.Instep7theinternalstructure(structuralvalidity,internalconsistencyandcross‐culturalvalidity\measurementinvariance)isassessed.Astheassessmentofreliabilityandmeasurementerrorrequiresanadditionalstep(i.e.understandinghowtheresultsofastudyinformyouaboutthereliabilityormeasurementerrorofaoutcomemeasurementinstrument),thesetwomeasurementpropertiesarenowassessedinaseparatestep,i.e.step8,apartfromtheassessmentofthemeasurementpropertiescriterionvalidity,hypothesestestingforconstructvalidity,andresponsiveness(i.e.step9).

Step6.Evaluatecontentvalidity

Instep6contentvalidityisevaluated.InthecurrentstandardsandcriteriaforassessingcontentvalidityofPROMs(6)emphasizeisputontherelevance,comprehensiveness,andcomprehensibilityofthePROMfortheconstruct,targetpopulation,andintendedcontextofuse.InthisassessmentalsothedevelopmentofthePROMisconsidered,specifically,theitemelicitationphaseandtheresultsfromthepilot‐testingphase.Theassessmentofcontentvalidityofothertypesofinstrumentsmaybedifferent,andmoreresearchisneededtodevelopstandardsandcriteriaforothertypesofmeasurementinstruments.

Assessingthecontentvalidityofmeasurementinstrumentsthatincludemultipleitems–eitherbasedonareflectiveorformativemodel–canheavilyleanonthestandardsandcriteriaforPROMs.Only,becauseprofessionalsareinvolvedinthemeasurement,thethreeaspectsofcontentvalidity(i.e.relevance,comprehensiveness,andcomprehensibility)shouldbeaskedtotheprofessionals.Dependingontheconstructofinterest,theseaspectscouldbeaskedtopatients,too,forexampleforPerFOMs,orClinROMsaboutsymptomsorseverityofconditions.

Fortheassessmentofcontentvalidityofmeasurementinstrumentsthatexistofasingleparameter(e.g.imaging‐basedparameters,orlaboratoryvalues),otheraspectsarelikelymorerelevant.Forexample,youshouldjudgewhetheritmakessensethatthemeasurementinstrumentindeedmeasurestheconstructitpurportstomeasure,basedontheoryandmedicalknowledge,andbasedontheclaimsbythemanufacturer.Inaddition,theunitofmeasurementshouldmatchtheconstructtobemeasured.Forexample,a6minutewalktest–expressedinthedistancecoveredoveratimeof6minutes–measureswalkingcapacity,ratherthanphysicalfunctioning(51).Ascurrentlynostandardsandcriteriaforcontentvalidityexist,facevalidity(whichisarathersubjectivejudgmentaboutwhetherthecontentoftheinstrumentindeedlooksasanadequatereflectionoftheconstructtobemeasured)couldbeassessedbythereviewer.

Step7.Evaluatetheinternalstructure

Instep7theinternalstructure(structuralvalidity,internalconsistencyandcross‐culturalvalidity\measurementinvariance)isassessed.Thisstepisonlyrelevantwhenthemeasurementinstrumentisamulti‐iteminstrumentbasedonareflectivemodel.Thestandards(1)andcriteria(5)providedforsystematicreviewsofPROMscanbeused.

Step8.Evaluatereliabilityandmeasurementerror

Next,instep8reliabilityandmeasurementerrorareassessed.Inchapter2and3wehaveexplainedhowtoassessthequalityofeachstudyonreliabilityandmeasurementerror.

Inasystematicreviewperstudy,youshouldfirstextractinformationabouttheelementsofacomprehensiveresearchquestion(seechapter2),thespecificICCmodelorformula,andtheresultsofeachstudy.Next,youshouldassessthestudyqualityusingthestandards(seechapter3),andassesstheresultsofeachstudy,bycomparingtheresultsagainstthecriteriaforgoodmeasurementproperties(5).Subsequently,youshouldsummarizeallevidenceforreliabilityandformeasurementerror,respectively,andgradethequalityoftheevidenceusingthemodifiedGRADEapproach(5).Basedonthisoverview,youcanrecommendonthebest‐evidencemeasurementprotocolforaspecificmeasurementinstrument.

Extractinginformation

InAppendix1weprovideanexampleofadataextractiontable.First,werecommendtoextractthesevenelementsofacomprehensiveresearchquestion,andtheresearch

questionasstatedbytheauthorsinthearticle.Basedontheelements,youcansubsequentlyformulateacomprehensiveresearchquestion.Next,werecommendtoextracttheinformationaboutthekeyelementsofthereview,i.e.theconstruct,population,typeofmeasurementinstrument,andmeasurementpropertiesofinterest.Theconstructtobemeasured(element3ofacomprehensiveresearchquestion),andthespecificmeasurementproperties(element4ofacomprehensiveresearchquestion)arealreadyextracted,sothetargetpopulationandthetypeofmeasurementinstrumentarerecommendedtobeextracted.Thetargetpopulationreferstothetargetpopulationofthespecificstudy.IntheexampleofSkeieetal.(19),thetargetpopulationwerepatientswithlow‐backpain.Thiscanbedifferentfromthestudypopulation(i.e.thesampleused)asextractedinitem7,or(slightly)differentfromthetargetpopulationofthereview(e.g.abroaderpopulation).InthestudyofSkeie,notonlypatientswithlow‐backpainwereincluded,butalsopatientswithotherspinalcomplaintssuchasmidbackpain,neckpain,and/orextremitypain,orevenpain‐freesubjects.ThetypeofmeasurementinstrumentreferstowhethertheinstrumentunderstudyisaClinROM,PerFOM,laboratoryvalue,aPROMoranObsROM.

Last,werecommendtoextractinformationaboutthestatistics:themodelorformulaused,theresult,and,ifapplicable,its95%confidenceinterval.Ifavailable,werecommendtoextractthevariancecomponents,ortheSDsampleorSDdifference(seealsochapter3.2formoreexplanation).Forordinalordichotomousdatawerecommendtoextracttherawnumbersinthecellsplusmarginaltotals.

RiskofBiasassessment

Thenextstepinthereview,istoassessthequalityofeachstudy,usingPartBoftheRiskofBiastooltoassessreliabilityandmeasurementerror(asdescribedinchapter3).Werecommendtousetheworst‐scorecountsmethodstocometoanoverallratingperstudy.InAppendix2weprovideanexampleofsuchatabletoorganizetheseratings.Werecommendthateachstudyisassessedbytwoindependentreviewers,andthattheycometoconsensus.

Comparisonagainstthecriteriaforgoodmeasurementproperties

Eachresultofeachsinglestudyonreliabilityormeasurementerrorisnowcomparedagainstthecriteriaforgoodmeasurementproperties(5).AsnocriteriafortheunweightedKappa,andCVwereprovidedintheguidelinesforsystematicreviewsofPROMs,weaddedthesemissingcriteria(seeTable8).Criteriafor%specificagreementaredifficulttoset,becausetheyare,justlikesensitivityandspecificity,highlydependentonthesituation.Asaruleofthumb80%mightbeused.

Table8.Extendedcriteriaforgoodreliabilityandmeasurementerror(adaptedfromPrinsenetal.(5))

Reliability

+ ICCor(weighted)Kappa≥0.70

? ICCor(weighted)Kappanotreported

– ICCor(weighted)Kappa<0.70

Measurementerror

SDCorLoAorCV*√2*1.96<M(C)IC1;%specificagreement>80%2

? MICnotdefined

–SDCorLoAorCV*√2*1.96>M(C)IC1;%specificagreement<80%2

1theM(C)ICvaluemaycomefromanotherstudy.2Sometimesahigherpercentageismoreappropriate;whensubstantiated,thiscouldbeappropriate,too.

Summarizingtheevidence

Tocometoanoverallconclusionofthereliabilityorthemeasurementerrorofanoutcomemeasurementinstrument,oneshouldfirstdecidewhethertheresultsfrommultiplestudiescanbecombined.Youshouldtaketwoaspectsintoaccountinthisdecision.1)Dotheresultsrefertothesameinformation(i.e.refertothesameunderlyingcomprehensiveresearchquestion).Resultsfromdifferentdesigns(i.e.differentcomponentswerevariedacrosstherepeatedmeasurements)giveyouotherinformationaboutthereliabilityofaninstrument,andthereforecannotsimplybesummarized.And2)Aretheresultsconsistent,thatisallresultsareeithersufficient(+)orinsufficient(‐).Incaseofinconsistencyinresults,werecommendtosearchforreasonsforthisinconsistency,e.g.differentdesignsorstatisticalmodels,differentpopulations,differentbackgroundofraters.Subsequently,subgroupsofstudiescanbesummarized.

Tosummarizetheevidence,youcaneitherqualitativelysummarizetheresults(e.g.describetherangeoftheresults)orquantitativelypooltheresults.Inreliabilitystudies,onlythepointestimateofanICCorCohen’skappaisusedtoconcludewhetherthespecificmeasurementinstrumenthassufficientreliability(e.g.inthecriteriathatweproposeabove).Therefore,itisnotnecessarytopoolthedatatoobtainamoreprecisepointestimate.

Themeasurementerrorreferstotheabsolutedeviationofthescorefromthe‘true’scoreortheamountoferrorinthescore.Thepointestimateofthemeasurementerrorparameterreferstothisdeviationorerror,andthereforeitisusedtoknowhowprecisethemeasurementinstrumentisabletomeasureapatient.Tocometoamoreprecisepointestimatesofthemeasurementerror,theparametersobtainedinstudieswiththesamedesign(i.e.thathavethesameunderlyingcomprehensiveresearchquestion)can

bepooled,whentheconfidenceintervalsarealsoreporting(whichcanbeobtainedusingthesamplesize(39)orbootstrappingmethods(52)).

Note,thatyoushouldonlysummarizeorpoolparametersofmeasurementerrorthatwerederivedfromthesamestudydesignandmodelorformulaused.Forexample,theSEMconsistency(eitherformula4or8,chapter3.2)andSEMagreement(formula2,chapter3.2)shouldnotbecombined.However,SEMconsistencyusingeitherformula4or6(chapter3.2)canbecombinedastheywillleadtothesameresult,andtheSDCconsistencyusingeitherformula5,7,or9(chapter3.2)canbecombined.ThesameresultsarefoundwhenusingeithertheSEMone‐wayrandomeffectsmodel(formula1,chapter3.2)orSEMagreement(formula2,chapter3.2).Thisisbecauseallsourcesofvariance(apartfromthevariancebetweenpatients)aretakenintoaccountinbothformulas.Therefore,theseparameterscanbecombined.

Handlinginconsistentresults.

Iftheresultsofstudieswiththesameunderlyingresearchquestionareinconsistent(e.g.bothsufficientandinsufficientresultsarefound),firstexplanationsforinconsistencyshouldbeexplored.Forexample,slightlydifferentstudypopulationsormethodswereused.Ifanexplanationisfound,subgroupsofstudies(e.g.nowbasedonthesamestudypopulation,orinwhichthesamesourceofvariationisvaried)canbesummarized.Theoverallconclusionfor(e.g.)reliabilitycansubsequentlybedrawnpersubgroup.Whentheexplanationisfoundinthequalityofthestudies(i.e.verygoodandadequatestudiesleadtoanotheroverallratingthandoubtfulandinadequatestudies),thedoubtfulandinadequatequalitystudiesmayonlybereported,butignoredinthisstep,andonlyverygoodandadequatequalitystudiesareconsideredtobedecisiveindeterminingtheoverallratingwhenratingsareinconsistent.Thisshouldbeexplainedinthemanuscript.

Ifstudieswiththesameunderlyingresearchquestionshowedinconsistentresults,andnoexplanationcanbefound,onecanconcludethatresultsareinconsistent.

WerefertotheUsermanualoftheCOSMINmethodologyforsystematicreviewsofPROMsformoreinformation.

Ratethequalityofthesummarizedresult

Ifmultiplestudiescanqualitativelybesummarized(e.g.therangeofresults)orquantitativelypooled,theoverallresultcanagainbecomparedtothecriteriaforgoodmeasurementproperties(seeTable8);youcanthenconcludethattheoutcomemeasurementinstrumenthaseithersufficient(+)orinsufficient(‐)reliabilityormeasurementerror.Oryoushouldconcludethattheresultsareinconsistent(±),or

indeterminate(?).Formoreinformation,werefertotheUsermanualoftheCOSMINmethodologyforsystematicreviewsofPROMs.

GradingthequalityoftheevidenceusingthemodifiedGRADEapproach

Aftersummarizingorpoolingallevidenceperoutcomemeasurementinstrumentforreliabilityandformeasurementerror,andratingthesummarizedorpooledresultsagainstthecriteriaforgoodmeasurementproperties,thenextstepistogradethequalityoftheevidence.Thequalityoftheevidencereferstotheconfidencethatthesummarizedorpooledresultsistrustworthy.WedevelopedamodifiedGRADE(GradingofRecommendationsAssessment,Development,andEvaluation)approachtogradetheevidenceashigh,moderate,loworverylow(5),basedonthe1)riskofbias(i.e.themethodologicalqualityofthestudies),2)inconsistency(i.e.unexplainedinconsistencyofresultsacrossstudies),3)imprecision(i.e.totalsamplesizeoftheavailablestudies),and4)indirectness(i.e.evidencefromdifferentpopulationsthanthepopulationofinterestinthereview).ThisprocedureisdescribedintheUsermanualoftheCOSMINmethodologyforsystematicreviewsofPROMs(5,45).

Drawconclusionon‘best‐evidencemeasurementprotocol’

Theresultsofreliabilitystudieswiththeirspecificdesignsinformyouwhetherasourceofvariation(forexamplethetrainingofarater,thespecificmachineused)importantlyaffectsthescore(i.e.themeasurement).Ifpossible,thissourceofvariationshouldbestandardizedorrestrictedinfuturemeasurements.Bylookingatallevidenceforvarioussourceofvariation,youcannowdrawconclusionsabouthowtostandardizeandrestrictthemeasurement,anddescribethisbest‐evidencemeasurementprotocol.

Step8.Evaluatecriterionvalidity,hypothesestestingforconstructvalidity,andresponsiveness

Instep8criterionvalidity,hypothesestestingforconstructvalidity,andresponsivenessisassessed.Thestandards(1)andcriteria(5)providedforsystematicreviewsofPROMscanbeused.

Steps10‐11:.Selecttheoutcomemeasurementinstrument

Thesteps10and11concernstheformulatingrecommendations(step10)andthereportingofthesystematicreview(step11).

Step10.Formulaterecommendations

Thegoalofasystematicreviewonmeasurementinstrumentsistogetanoverviewofallavailableevidenceonthequalityofoutcomemeasurementinstrumentsthatmeasureaspecificconstructinadefinedpatientpopulation.Basedonthisoverview,andtakingaspectsoffeasibilityandinterpretabilityintoaccount,werecommendyoutoformulateyourrecommendationsaboutthemostsuitableoutcomemeasurementinstrument.Tocometoanevidence‐basedandfully‐transparentrecommendation,werecommendtocategorizetheincludedmeasurementinstrumentsintothreecategories.Pertypeofmeasurementinstrumentyoucanconcludewhichinstrument(s)arerecommended(categoryA)orpromising(categoryB),orinsufficient(categoryC)andshouldnotbeusedanymore.

Category(A):

Werecommendusingdifferentdefinitionsofthecategory(A),dependingonthestructureofthemeasurementinstrument:

Multi‐itemreflectief

Evidenceforsufficientcontentvalidity(anylevel),ANDsufficientinternalconsistency(atleastlowquality,meaningalsosufficientstructuralvalidity)

Multi‐itemformatief

Evidenceforsufficientcontentvalidity(anylevel)

Singleitem(singleparameter)(nogoldstandard)

Sufficientfacevalidity(ratedbye.g.thereviewersteam),ANDevidenceforsufficientreliability(anylevel)

Singleitem(goldstandardavailable)

Evidenceforsufficientcriterionvalidity,ANDevidenceforsufficientreliability(anylevel)

Category(B):outcomemeasurementinstrumentnotcategorizedas‘A’or‘B’.

Category(C):outcomemeasurementinstrumentwithhighqualityevidenceforaninsufficientmeasurementproperty.

Step11.Reportthesystematicreview

InaccordancewiththePRISMAStatement(53,54),werecommendtoreportthefollowinginformation:(1)thesearchstrategy(forexampleonawebsiteorinthe(online)supplementalmaterialstothearticleatissue),andtheresultsoftheliteraturesearchandselectionofthestudiesandmeasurementinstruments,displayedinthePRISMAflowdiagram(includingthefinalnumberofarticlesandthefinalnumberofmeasurementinstrumentsincludedinthereview)(Appendix3);(2)thecharacteristicsoftheincludedmeasurementinstruments,includingaspectsoffeasibilityandinterpretability(Appendix4);(3)thecharacteristicsofthestudies,includingthecharacteristicsoftheincludedpatientpopulations,andpopulationofincludedprofessionals(Appendix5);(4)themethodologicalqualityratingsofeachstudypermeasurementpropertypermeasurementinstrument(i.e.verygood,adequate,doubtful,inadequate),theresultsofeachstudy,andtheaccompanyingratingsoftheresultsbasedonthecriteriaforgoodmeasurementproperties(sufficient(+)/insufficient(‐)/indeterminate(?)).IntheUserManualforconductingsystematicreviewsofPROMs(45)anexampleisprovided.InAppendix6weprovideexamplesspecificallyforcolumnsonreliabilityandmeasurementerror.ThetablecouldbepublishedforexampleasAppendixorsupplementalmaterialonthewebsiteofthejournalonly;(5)aSummaryofFindings(SoF)tablepermeasurementproperty,includingthepooledorsummarizedresultsofthemeasurementproperties,itsoverallrating(i.e.sufficient(+)/insufficient(‐)/inconsistent(±)/indeterminate(?)),andthegradingofthequalityofevidence(high,moderate,low,verylow).IntheUserManualforconductingsystematicreviewsofPROMs(45)anexampleisprovided.InAppendix7weprovideexamplesspecificallyforcolumnsonreliabilityandmeasurementerror.TheseSoFtables(i.e.onepermeasurementproperty)willultimatelybeusedinprovidingrecommendationsfortheselectionofthemostappropriatePROMforagivenpurposeoraparticularcontextofuse.

Appendix1.DataExtractiontableofrelevantinformationforeachincludedstudyinasystematicreview.

Extractionitem Instruction Study1 Study2Elementsofacomprehensiveresearchquestion1.Nameoftheinstrument

Alternatively:typeofinstrumentandparameter

2.Versionorwayofoperationalization

Allrelevantcomponentsthatareknownorexpectedtoinfluencethescore,andwhicharestandardizedorrestricted(facetofstratification(23))

Equipment:Preparatoryactions:

Unprocesseddata/samplecollection:Dataprocessingandstorage:

Assignmentofthescore/determinationofthevalue:

3.Construct Descriptionofwhatisbeingmeasured

4.Measurementproperty

Reliabilityand/ormeasurementerror

5.Componentsthatwillberepeated

e.g.wholemeasurement(i.e.allcomponents)orsomeofthecomponent

6.Source(s)ofvariationvaried

Componentswhichisvariedacrossthemeasurements(i.e.focusofanalysis;facetofgeneralizability(23))

7.Patientpopulation

(i.e.facetofdifferentiation(23))

Theresearchquestion

Publishedresearchquestion

Asformulatedbytheauthors

Comprehensiveresearchquestion

Asformulatedbythereviewer

Additionalkeyelementofresearchaimofthereview

Targetpopulation Descriptionofthepopulationtowhichtheauthorswanttogeneralize

Typesofmeasurementinstrument

e.g.ClinROM,PerFOM,laboratoryvalue,PROMorObsROM

Statisticalinformationandresults

Modelorformulaused

Statisticalmodel

Result e.g.results(95%CI)ofICC,kappa,SEM,LoAandsystematicdifference

Variancecomponents

Allreportedvariancecomponents

Applycriteriaforgoodmeasurementproperty*

sufficient(+),insufficient(‐),orindeterminate(?)

*althoughthisisarating,andnotdataextraction,weincludeithere,astherequiredinformationtomaketheratingisextractedhere.

Appendix2.RiskofBiasratingsperstandardperstudy

RiskofBiasrating study1 rater1 rater2 consensusDesignrequirements 1 Stabilityofthepatients 2 Timeinterval 3 Similarityofmeasurementcondition 4 Administationwithoutknowledgeof

scoresorvalues 5 Scoreassignmentordeterminationof

valueswithoutknowledgeofthescoresorvalues

6 Otherimportantflaws Statisticalmethods 7 Forcontinuousscores:ICC 8 Forordinalscores:Kappa 9 Fordichotomous/nominalscores:

Kappaforeachcategoryagainsttheothercategoriescombined?

Finalrating

Appendix3.ExampleofaFlow‐chart

Appendix4.Exampleofreportingtableoncharacteristicsoftheincludedmeasurementinstruments.

Name(referencetofirstarticle)

Construct Intendedcontextofuse

Best‐evidencemeasurementprotocol

Targetpopulation

Typeofmeasurementinstrument

Feasibilityaspects

Interpretabilityaspects

LMMthickness(19)

Thicknessofrestingmuscle

Evaluation Trainingdiagnosticultrasound.Specificinstructionsforpatient,andprobepositions.

Patientswithlowbackpain

Ultrasound Meanscoreinmixofpainpatientswas27.9mm(±3.2)

LMMcontraction(19)

Comparisonofthethicknessofrestingmusclewiththatofactivatedmuscle

Evaluation Trainingdiagnosticultrasound.Specificinstructionsforpatient,andprobepositions.

Patientswithlowbackpain

Ultrasound Meanscoreinmixofpainpatientsranges1.3mm(±1.7)–3.5mm(±2.6)

Othercharacteristicswhichmaybeextractedare:conceptualmodelused,recommendedbystandardizationinitiatives,fullcopyavailable,fitforpurpose(diagnostic,prognostic,evaluation).

Aspectsoffeasibilityare,forexample,completiontime,licensinginformationandcostsofaninstrument,typeandeaseofadministration.Feasibilityappliestoboththepatientsandtheprofessionalwhoareinvolvedinthemeasurement.ItmaybeconsideredtoreportthisinformationinaseparateTable.

Aspectsofinterpretabilityreferto1)interpretabilityofsinglescores(e.g.informationonthedistributionofscoresinstudypopulationorotherrelevantsubgroups,andfloorandceilingeffects),and2)interpretabilityofchangescores(i.e.M(C)ICvalues).

Appendix5.Exampleofreportingtableoncharacteristicsofthestudypopulations.

Measurementinstrument

Reference Measurementpropertyassessed

Patientpopulation Professionalpopulation Responserate

Samplesize

Patientcharacteristics Samplesize

Characteristicsofprofessionals

LMMcontraction

(19)Study2 Reliability,measurementerror

30 47%female,agemean(SD)37(±12);LBPn=20;neck/midbackpainn=5;extremitypainn=1;painfreen=4

2 Chiropractorsexperiencedindiagnosticultrasoundforthemusculoskeletalsystem,i.e.4and8yearsresp.,withapostgraduatediplomaindiagnosticultrasound.Beforethestudy.bothdevelopedtheprotocolofdiagnosticultrasoundthatwasappliedinthisstudy.

(19)Study3 Reliability 30 50%female,agemean(SD)38(±11);LBPn=23;neck/midbackpainn=7

(19)Study4 Reliability,measurementerror

30 43%female,agemean(SD)40(±11);LBPn=20;neck/midbackpainn=6;extremitypainn=3;painfreen=1

Patientcharacteristicsreferto,e.g.age,gender,diseasecharacteristics(diagnosis,diseaseduration,diseaseseverity),setting,andgeographicallocation.

Ratercharacteristicsmayreferto,e.g.professionalbackground,specifictrainingreceived,oryearsofexperience.

Appendix6.OverviewTableofqualityandresultsofstudiesonreliabilityandmeasurementerror.

Measurementinstrument(MI)(ref)

TypeofMI Reliability Measurementerrorn Studyquality Result(rating) N Studyquality Result(rating)

LLMcontractionscore(study2)(19)

Ultrasound 30 Adequate 0.97(0.92‐0.98) 30 Adequate LoA[−0.94;1.22mm]

Ultrasound 30 Adequate 0.94(0.88‐0.97)

Ultrasound 30 Adequate 0.97(0.94‐0.99) 30 Adequate LoA[−1.32;1.25mm]

LLMcontractionscore(ref)

Pooledorsummaryresult(overallrating)

90 0.94‐0.97(+) 90 SDCconsistsncy=1.08;1.29a

acalculatedfromLoA

Appendix7.SummaryofFindingsTablesforReliabilityandMeasurementerror.

BasedonthestudiesonreliabilitydescribedbySkeie(19)

Reliability Summaryresult Overallrating Qualityofevidence

UltrasoundmeasurementoftheLMMcontractionscore–best‐evidencemeasurementprotocol:rater,dayandactivemotortasksperformedbeforemeasurementwerenotofinfluence

RangeICC:0.94‐0.97 Sufficient High(twostudiesofadequatequality)

MeasurementinstrumentB–

BasedonthestudiesonmeasurementerrordescribedbySkeie(19)

Measurementerror Summaryresult Overallrating Qualityofevidence

UltrasoundmeasurementoftheLMMcontractionscore–best‐evidencemeasurementprotocol:rater,dayandactivemotortasksperformedbeforemeasurementwerenotofinfluence

RangeSDCconsistsncy:1.08‐1.29

MIC=notassessed

MeasurementinstrumentB–

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