Wednesday, December 23, 2009

Gelman on Becker and Dubner

One reason I enjoy reading Andrew Gelman is that he thinks about some of the same statistical issues that I do.

Another is that he is a really smart fellow who does not think like an economist but still reads and comments on economics articles and blogs. Today's example is his long, and misguided, criticism of a statement of Becker's, repeated by Dubner, that
According to the economic approach, therefore, most (if not all!) deaths are to some extent "suicides" in the sense that they could have been postponed if more resources had been invested in prolonging life.
What Becker is really saying is that people have things other than just duration of life in their utility function. What could be less controversial than that? The wording in the quotation serves the pedagogical purpose of highlighting an implication of the fact that we care about things other than just quantity of life, namely that we all choose to have shorter lifetimes, in an expected value sense, than we would if that were the only thing we were maximizing.

This seems completely obvious to me, but then I am an economist!

One might go farther and note problems with Gelman's criticisms:

1. Gelman argues against the "all" in favor of the "most" by noting that some people really do die in accidents even if they only have duration of life in their utility functions. I agree but think that the "all" is not intended seriously in the original statement.

2. Gelman argues that some methods that directly prolong life might have indirect effects that cause them on net to decrease expected length of life. This is surely true, but to the extent that agents understand this they are not behaving rationally in undertaking such methods. As such, this criticism is beside the point unless accompanied by an argument that agents have already undertaken all actions that yield a net increase in duration of life. And that is clearly false, as Gelman would surely agree.


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