Daniel Kahneman, Olivier Sibony & Cass R. Sunstein - Noise - A Flaw in Human Judgment (William Collins, 2022) ****

Daniel Kahneman's "Thinking, Fast and Slow" became a global bestseller, and rightly so, even if many of the book's core positions have been challenged by some cognitive scientists. Be that as it may, the book managed to open many minds to relfect on our own inuitive way of thinking, often very fast and even subconsciously, rarely with considered and conscious rationality. Driving that message home to us humans is already a major achievement, even if I'm not too optimistic about what it actually leads to in practice. 

"Noise" will probably not be a bestseller at the same level, yet it also deserves to be read by many. The core proposition of the book is that we all have a decision-making 'bias' that is linked to our perspective, culture, education, profession, etc. This 'bias' is well understoord by anybody involved in research, in opinion-polling or other levels of understanding decision-making. At the same time there is also 'noise' in the system, a problem of the same nature that is less widely acknowledged. "Noise" is the variation in choices or decisions made based on the same data, and that demonstrate a lack of coherence within an organisation or within the same person. 

The book gives dozens and dozens of examples of for instance claims administrators in insurance companies who give entirely different sums to claimants even if the damage is the same, or judges who give totally different sentences for identical crimes, or doctors who give totally different diagnoses for the same presented symptoms by patients. The stunning factor in the given examples are not only that there is variation in their decisions, but how wide the variations can be, as from three months to three years in the context of court sentences. A even more stunning fact is the variation by one and the same individual. Kahneman and colleagues mention studies that were conducted by presenting the same cases to the same judges or doctors six months after the first evaluation. The same judges and doctors came to a completely different decision so many months later. Some of these differences may even change depending on the moment of the day. Judges are more lenient with a full stomach, and less lenient on an empty one. The same is true with doctors apparently. 

We don't want to judge judges or doctors here, but show how we all should reflect on our own inconsistencies in judgment. In that respect, this book is again an eye-opener for anyone interested in the quality of our thought processes. 

The only downside in the book is the lack of recent data to substantiate their positions. Many of the studies that I double-checked had data from the '90s. It may be that nothing has changed since then, but I think that especially in medicine, many things have changed, including better diagnostics and the use of artificial intelligence to help mitigate the problems mentioned in the book. 

Recommended reading.