Abstract
This paper examines the determinants of public procurement prices using comprehensive data on pharmaceutical purchases by the Chilean public sector. We start by estimating the extent to which different public agencies pay different prices for the same product. These buyer effects are sizable, and the difference between average prices paid by buyers at the 10th and 90th percentiles is 16%. Our main set of results is related to the role of market structure. The variation in market structure explains three times more variation in procurement prices than buyer effects. Moreover, using exogenous variation from patent expirations, we estimate that the entry of an additional vendor decreases average procurement prices by 11.7%, which is 72% of the gap between average prices paid by buyers at the 10th and 90th percentiles of the distribution of buyer effects. These results suggest that supply-side factors are key determinants of public procurement prices and that their quantitative importance may exceed that of demand-side factors previously emphasized in the literature.