Three analytical traps in accident investigation

I recently watched a video on mistakes investigators make in accident investigating. It was worth watching but because its video it is difficult to skim or remember. This blog post is to make it to write down what I learned in a textual format to make it easier to find and remember later

This is the video:

The three mistakes were

1. Counterfactual reasoning ¹

This is when the investigator discusses events that never occurred. For example:

If the operator had clicked the button the outage would not have happened

1. Normative Language ²

This is when the investigator inserts their own values into. For example:

The crew mismanaged the plane during ascent.

Here the phrase mismanaged indicates that the crew did something wrong. Instead it would be better to explain why the crew thought what they did was actually correct. The high level idea of incident analysis and investigating is assuming that all actions made sense at the time they took place and understanding why that it so.

1. Mechanistic reasoning ³

This flaw is assuming that if the subcomponents of the system were operating correctly and safely then the accident would not have occurred. For example:

The operator delayed deploying the fix due to unfamiliarity with the CI pipeline.

Here we assume that if only the operator was clueful about the system, then everything would have worked out.

and a bonus:

1. Cherry Picking Data ⁴

This one is easy: only revealing the data that is relevant to the pre-conceived point one is trying to make.