A large theoretical literature assumes that experts differ in terms of preferences and the distribution of their private signals, but the empirical literature to date has not separately identified them. This paper proposes a novel way of doing so by relating the probability a member chooses a particular policy decision to the prior belief that it is correct. We then apply this methodology to study differences between internal and external members on the Bank of England’s Monetary Policy Committee. Using a variety of proxies for the prior, we provide evidence that they differ significantly on both dimensions.