Human Factors &PostMortems

Daniel Schauenbergd@etsy.com@mrtazz

We deploy quite a lot

MTTR

MTTR>

MTBF

realtalk:things break

New View

Complex Socio-Technical Systems

Erkenntnis und Irrtum fließen aus denselben

psychischen Quellen; nur der Erfolg vermag beide

zu scheiden.— Ernst Mach, Erkenntnis und Irrtum (p. 116)

Things made sense at the time

People don't come to work to do a bad job

Nietzschean Anxiety

So I always get off the hook whatever I do?

There is a difference between explaining and

excusing human performance.

— Sidney Dekker, The Field Guide to Understanding Human Error (p. 196)

BlamelessPostmortems

Open Meeting

Everybody is Invited

Whathappened?

Timeline

Describe the pastDon't excuse it away

The Facilitator

Guide the Discussion

Look out for indicators of Old View

thinking

Counterfactuals

- she should have- if he would have- if they just had

- you failed to

Biases

Hindsight BiasConfirmation Bias

Outcome Bias

there are many more

Who is in charge?

Etsy School

Taught Facilitator Course

3 x 90 minutes

Remediation Items

incorporate learning and takeaway from

the meeting

turn surprises into known factors

MORGUE

https://github.com/etsy/morgue

Near Miss

Pre Mortem

"Hey all, I just ran rm -rf $DIR/ and since the variable was empty

I deleted my whole VM. This would have been bad in

production. Don't do that."

ArchitectureReviews

OperabilityReviews

It is also worth pointing out that the bias towards

investigating failures rather than success itself represents a trade-off.

— Erik Hollnagel, The ETTO Principle: Efficiency-Thoroughness Trade-Off

Investigate Success

Why did it work?

Human Error is where you stopped looking

peakscale.com/postmortems

codeascraft.com

etsy.com/codeascraft/talks

etsy.com/careers

Questions?

Human Factors &PostMortems

Daniel Schauenbergd@etsy.com@mrtazz