A predetermined distribution type of a number of selections of an advertisement within a predetermined time period for a predetermined phrase and having a predetermined advertisement location is specified. A parameterization of a mean of the predetermined distribution type is also specified. The mean is determined using a hierarchical Bayesian model, based on the predetermined distribution type, the parameterization, and historical data regarding a number of actual selections of the advertisement for each of a number of phrases similar to the predetermined phrase. The mean corresponds to an average number of selections of the advertisement within the predetermined time period for the predetermined phrase and having the predetermined advertisement location, as predicted by the model.