A Proof of Blackwell's Theorem
Sciences Po Economics Discussion Papers
Paris : Département d'économie de Sciences Po
Sciences Po Economics Discussion Papers : 2017-06
This note gives a new proof of Blackwell’s celebrated result. The result is a bit stronger than the classical version since the action set and the prior are fixed, and only the utility of the decision maker varies. I show directly that a decision maker has access to a larger set of joint distributions over actions and states of the world if and only if her information improves in the garbling order.