Theoretical and experimental investigations of the performance of keyword auction mechanisms

Two keyword auction mechanisms, the Generalized Second‐Price auction (GSP) and the Vickrey‐Clarke‐Groves mechanism (VCG), were compared theoretically and experimentally. The former is widely used in practice; the latter is not, but it has a dominant strategy equilibrium where all participants bid their true values. In the theoretical investigation, by applying the “locally envy‐free Nash equilibrium” to the VCG, we found that the allocations are efficient and that upper and lower bounds of the auctioneer's revenue coincide in the two mechanisms. A laboratory experiment, in which the revenues and efficiencies were similar in both mechanisms, supported this result.     

A REFUTATION OF THE COMMODITY EXPLOITATION THEOREM

This note is to show that the generalized commodity exploitation theorem put forward by Bowles and Gintis and Roemer is nothing but an alternative form of the Hawkins–Simon condition for given technical data, and that it has nothing to do with exploitation. That is, the Hawkins–Simon condition means a mere possibility of an economic system to produce a surplus in each commodity, and as such does not guarantee the existence of positive profits. To consider exploitation or the existence of positive profits, we need to introduce prices at which unequal exchanges may be carried out.