Updated Priors (Ryan Decker) reviews Piketty

Here is one good part of a consistently good and interesting review:

Most of the analysis in the book is more about accounting than economics. Piketty takes nearly everything as exogenous then divides things arithmetically. His ubiquitous r > g heuristic takes both sides of the inequality as given for almost the entire book. Lines like “the richest 10 percent appropriate three-quarters of the growth” (297) enable lazy readers to avoid thinking about what actually determines income. Language about “appropriation” suggests that we live in an endowment economy, as does the claim that post-World War I wealth inequality fell “so low that nearly half the population were able to acquire some measure of wealth” (350). Endogeneity, anyone? Taking income as exogenous leads to other large problems with inference, such as the claim that “meritocratic extremism can thus lead to a race between supermanagers and rentiers, to the detriment of those who are neither” (417). Piketty does not consider the possibility that this race results in more income than otherwise, nor does he consider the notion that an increase in the bargaining power of elite executives could actually come at the expense of capital owners rather than workers. I’m not making an argument for either here; I’m simply suggesting that Piketty’s ideological quips don’t deserve the certainty with which he delivers them. Models with endowment economies have their purposes, but a 600-page book should be able to relax such strict assumptions. His criticisms of mathematical economics (32, 574) are not surprising given that he relies so heavily on assumptions and mechanisms that would be highly vulnerable to criticism if they were forced into the transparency of a formal model.

Hat tip goes to Angus.


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