Skin in the Game

Taleb argues that anyone who makes a decision affecting others must bear a share of the downside, and that most institutional failure traces to a broken link between decision and consequence. He applies the rule to bankers rescued by the state, to interventionist policy officials, to analysts and consultants who bear no cost for wrong advice, and to academics whose theories are never tested by exposure.

The book is organised around several distinct claims. Symmetry is an ethical requirement and also a filter for reliable information, since a person with exposure reveals more by their positions than by their statements. The minority rule states that an intransigent minority with a non-negotiable preference imposes its choice on a flexible majority, which explains outcomes such as most drinks being kosher. Taleb also distinguishes ensemble probability from time probability and argues that the difference explains why an individual with a ruin risk should not use expected value reasoning.

He attacks what he calls the intellectual yet idiot, meaning credentialed people who prescribe for populations whose lives they do not share, and he argues that the Lindy effect gives the survival of an idea or practice more evidentiary weight than a study does.

The book repeats material from Antifragile and Fooled by Randomness. The argument moves between ethics, epistemology and probability without keeping them separate, and the polemical passages consume space. The minority rule chapter and the ergodicity argument are original and useful. The insult-heavy sections are not. Practitioners use this book mostly as a way of checking whether an adviser's incentives match their advice.

Former options trader; Distinguished Professor of Risk Engineering, NYU Tandon; scientific adviser to Universa Investments

The Incerto is the primary source for how markets and institutions handle tail risk, and the accompanying technical work supplies the mathematics others cite.

NYU Tandon, Universa Investments