Ohio School Milk Markets: An Analysis of Bidding
分析1980年代俄亥俄州学校牛奶采购中的投标数据，发现辛辛那提一组企业的行为与合谋一致，合谋使市场价格平均提高约6.5%。
We examine the institutional details of the school milk procurement process, bidding data, statements of dairy executives, and supply characteristics in Ohio during the 1980s. We compare the bidding behavior of a group of firms in Cincinnati to a control group. We find that the behavior of these firms is consistent with collusion. The estimated average effect of collusion on market prices is about 6.5%, or roughly the cost of shipping school milk about 50 miles.