In the context of an allocation game, this paper analyses the proposer’s reported beliefs about the responder’s willingness to accept (or reject) the proposed split of the pie. The proposer’s beliefs are elicited via a quadratic scoring rule. An econometric model of the proposer’s beliefs is estimated. The estimated proposer’s beliefs are then compared with the actual responder’s choices. As a result of this comparison, we observe that the proposer tends to underestimate the empirical acceptance probability, especially when the slice of the pie allocated to the proposer is large.