A second person has actually done the risky task
Having a second person perform a critical task under real conditions, at least once, converts a documented procedure into a demonstrated capability and surfaces the assumptions the document does not contain.
Do this firstWrite down decisions, with the reasoning and the alternatives
Someone who is not the expert does the restore, runs the failover, performs the release — while the expert watches and does not touch the keyboard.
Every gap this finds is a gap the document had. The exercise is uncomfortable and slow the first time, which is precisely the information: that discomfort is what an incident would have felt like, experienced on a day when nothing is broken and the expert is in the room.
The decoy
A runbook. It is written by the person who knows and read by nobody until an incident, at which point its unstated assumptions are discovered by someone with no context and a clock running.
Evidence
- Organizational Volatility and its Effects on Software Defects — II"recent departures from an organization were associated with increased probability of customer-reported defects" after controlling for size, coupling, release count and experience. Notably, the number of newcomers joining was NOT a significant predictor — the cost is in people leaving, not in onboarding.
Last reviewed 2026-08-19.