Social Science Bites

When human judgment enters the picture, so too will errors in human judgment. Think of this as “noise,” just as you might think of a signal-to-noise ratio in an audio signal. And just as in listening to music, this noise is not a feature, but a flaw. In the context of human action, management professor at HEC Paris and former McKinsey senior partner Olivier Sibony defines “noise” as the unwanted variability in human judgment. “When you look at how people make a professional judgment, there is an average error … and that is what has traditionally been called bias in statistics and in the study of judgment. But when you have already identified bias, there is something left, and that is the unshared error, the unwanted variability of errors, that is noise.” In a new book, Noise: A Flaw in Human Judgment, by psychologist and Bites alumnus Daniel Kahneman, Sibony, and Harvard law professor Cass Sunstein (author of Nudge), the trio look at the lottery that noise creates in social outcomes, and discuss ways to