Breaking tunnel vision during an incident
Whether you can counter confirmation bias under pressure.
Call out the assumption, ask for disconfirming evidence, list parallel hypotheses, split responders to investigate them, and anchor on what changed and the data.
What's really being asked
Whether you can recognize and counteract confirmation bias and anchoring during an incident, where stress pushes teams to latch onto the first plausible story and ignore contradicting evidence.
The full answer
First, name it: as incident lead, explicitly state that the current theory is one hypothesis among several and that you want to avoid tunnel vision. Demand disconfirming evidence by asking what observation would prove this theory wrong, and check whether the data actually supports it or just fits the story. Run a quick structured brainstorm of alternative hypotheses, including the most recent changes (deploys, config, traffic, dependency incidents) since 'what changed' is the highest-yield starting point. Then parallelize: assign different responders or pairs to investigate distinct hypotheses simultaneously rather than the whole team crowding one theory, with the IC tracking each thread. Re-anchor everyone on observable signals (metrics, logs, traces, the timeline) instead of speculation. If the leading theory cannot be confirmed in a bounded time, explicitly move on. Throughout, keep mitigation efforts (rollback, failover) running in parallel with diagnosis, since restoring service does not require knowing the full root cause.
Interview question
The team is convinced an unproven theory explains an ongoing outage. What is the most effective lead action to broaden the investigation?
- a.Order everyone to keep digging into the single theory until it is proven
- b.Halt all investigation until a senior engineer arrives
- c.Assign responders to investigate multiple hypotheses in parallel and ask what would disprove eachCorrect
- d.Restart every service repeatedly until the symptom disappears
Why? this is the answer
Parallelizing across hypotheses and seeking disconfirming evidence breaks anchoring and finds the real cause faster. Forcing the whole team onto one unproven theory risks wasting the entire response if it is wrong.
Just read this? Test yourself on what you have been reading.
- #sre
- #incident-response
- #cognitive-bias
- #troubleshooting
- #leadership
Put your scrolling time to good use
Learn one idea, try a quiz and save useful cards for revision. Tezvyn makes it easy to learn and stay current in your tech field, a few minutes at a time.
The iPhone app is on the way
We are building it. Until it lands, nothing here is held back from you: every interview card, your saved cards, streaks and the job board all work in Safari, plus hundreds of free practice quizzes of thirty questions each. Sign in and it all carries over to the app the day it arrives.
Want it as an icon? Tap Share at the bottom of Safari, then Add to Home Screen. It opens full screen and the cards you have read stay available offline.
We are hiring for this. Open roles that interview on sre — each one lists the topics its interview covers.
See open roles