We investigate the problem of a principal contracting an expert to provide a probability forecast for a binary event. Experts can research this event at a cost unknown
to the principal. We present a truthful and efficient mechanism for the principal's
problem of contracting an expert. This results in the principal contracting the best
expert to do work equivalent to having the second best expert in-house.
We discuss several extensions to this mechanism. The contracts in [9] are used to
generalize our mechanism to non-binary events. We consider how the mechanism is
affected when the principal and experts have a maximum acceptable risk and cannot
afford to exceed a certain budget. Finally, we discuss the result of the experts changing
their belief before the mechanism - either due to a signal they received or due to costly
research that they carry out