Rationalizing rational expectations: characterizations and tests
Résumé
In this paper, we build a new test of rational expectations based on the
marginal distributions of realizations and subjective beliefs. This test is widely
applicable, including in the common situation where realizations and beliefs
are observed in two dierent datasets that cannot be matched. We show that
whether one can rationalize rational expectations is equivalent to the distribu-
tion of realizations being a mean-preserving spread of the distribution of beliefs.
The null hypothesis can then be rewritten as a system of many moment inequal-
ity and equality constraints, for which tests have been recently developed in the
literature. The test is robust to measurement errors under some restrictions
and can be extended to account for aggregate shocks. Finally, we apply our
methodology to test for rational expectations about future earnings. While
individuals tend to be right on average about their future earnings, our test
strongly rejects rational expectations.