If the analyst has only the fingerprint to look at – and no other information about the case – and decides on one occasion it is a match and on another it is inconclusive, that’s noise. One example is fingerprint analysis, with the same analyst making different judgements about the same print at different points in time. Noise: A Flaw in Human Judgment, by Daniel Kahneman, Olivier Sibony & Cass R. Kahneman’s previous book Thinking, Fast and Slow, published in 2011, brought much of this work to the attention of a broader audience and cemented his reputation as a foundational figure in the understanding of human behaviour. Their work, beginning in the late 1960s, laid the foundation for the new field of behavioural economics, which challenged the economic orthodoxy that decisions are rational. Kahneman won his Nobel prize for his pioneering work with fellow Israeli psychologist Amos Tversky on how cognitive biases shape judgement. This is “noise” – the reason human judgements that should be identical vary – which Daniel Kahneman, one of the world’s best-known psychologists and winner of the 2002 Nobel Prize in Economics, tackles in his latest book, Noise: A Flaw in Human Judgment.

Now imagine the reason for the difference is because the doctors have made their diagnosis in the morning or afternoon, or at the beginning or the end of the week. Imagine two doctors presented with identical information about the same patient giving very different diagnoses.

Daniel kahneman books