This book is excellent. Much like Kahneman’s definitive book on bias, Thinking Fast and Slow, Noise provides an excellent, fairly comprehensive treatment of another source of error in human judgement, which the authors define as noise. Noise is, as a term in this book, used to describe inconsistency in human judgment, as opposed to bias, which is a systematic departure from “correct” results. There is some overlap in terms here, as, for example, hungry judges systematically make harsher decisions, which is referred to as bias in Thinking Fast and Slow, but because we’re looking at error across the entire range of outcomes in a different way here, is called occasion noise. I do not believe this detracts from what the book brings to the table, but it’s worth noting that in this book, bias is used to refer to the difference between the average outcome and the “correct” outcome, or other errors across the range of outcomes such as minorities being treated differently in cases where there isn’t a “correct” outcome to measure.

What this book does not do is claim that all noise should be completely eliminated. Eliminating noise has costs. However, a wide disparity of outcomes in similar cases can be extremely unfair. Should two people with similar histories and mitigating/aggravating factors have several years of difference in sentencing for the same crime? Should the luck of who evaluates your insurance policy or what mood they’re in when they do make hundreds of dollars in difference to your premiums or policy payouts? Certain types of judgements are judgements where inconsistency is inherently unfair.

Noise looks at these judgements. It looks at hiring decisions where projection is inherently difficult and outcomes are hard to evaluate. It looks at expert judgement in fields like forensics where experts are asked to make evaluations of objective facts and whether there is noise in those outcomes as well.


I feel like I should be writing many more paragraphs about this book, but for now I’ll leave it here. This book is held to a high standard of rigor and is evidence backed throughout, again in line with Kahneman’s Thinking, Fast and Slow. The two books combine to provide an extreme amount of information on how to improve your judgement as an individual or an organization. I highly recommend this book and it will be very close to the top of my list of “must read” books on intelligence and the human brain.



There are three authors here and I don’t wish to downplay any role of Cass Sunstein or Oliver Sibony, which I am obviously not in position to evaluate. This book has led me to investigate their other work and likely will result in me reading at least one from each. However, Kahneman is the most well known partly because he’s one of the most influential figures in the field of human judgement, widely cited by psychologists and behavioral economists, and Thinking Fast and Slow is in my opinion is probably the best book on the brain everyone should read.