A follow-up of sorts to Thinking, Fast and Slow, this book focuses on 'noise' — unwanted, often invisible variability in judgements that should be consistent, distinct from bias (which is a systematic, predictable error). The same underwriter, doctor or hiring manager often makes meaningfully different judgements on similar cases depending on factors as trivial as time of day or mood.
Key lessons
- Noise — unwanted variability in judgements that should be consistent — is a distinct problem from bias, and often invisible without deliberate measurement.
- The same person can make measurably different judgements on similar cases depending on irrelevant factors like time of day.
- Structured decision processes and checklists reduce noise more reliably than trusting expert intuition alone.
- Organisations rarely measure their own noise, because doing so requires deliberately testing consistency, not just checking individual decisions.
Unwanted inconsistency in repeated judgement calls (pricing, hiring, reviews) is usually invisible and rarely measured — structuring the decision process reduces it far more reliably than trusting expert judgement alone.
What’s aged well
Recent and grounded in rigorous research; likely to remain a key reference on decision quality.
What feels outdated
Nothing significant given recent publication.
The Business Stuff verdict
Dense and demanding, but genuinely important for any business making repeated, high-stakes similar judgement calls.
Three things to actually do after reading it
- Identify one repeated judgement call in your business (pricing, hiring) and test how consistent it actually is across similar cases.
- Introduce a simple structured checklist for one high-stakes recurring decision to reduce unwanted variability.
- Separate 'is this decision biased' from 'is this decision noisy' the next time a judgement call goes wrong.
If you liked this, read next
Five similar books
- Thinking, Fast and Slow (Daniel Kahneman)
- Superforecasting (Tetlock & Gardner)
- Thinking in Bets (Annie Duke)
- The Checklist Manifesto (Atul Gawande)
- Predictably Irrational (Dan Ariely)
