In this paper we analyze the effect of the design of yardstick competition on consumer prices, by means of a theoretical analysis as well as an economic experiment. We compare four different designs: the uniform yardstick, the unweighted uniform yardstick, the discriminatory yardstick, and the best-practice yardstick. The effect of a specific design on prices depends on two separate mechanisms, one which affects the incentive power to increase productive efficiency and another which affects the risk of collusion. We show theoretically that for the best-practice yardstick, which is widely applied in several industries in a number of countries, these two mechanisms point in the same direction (high prices), which is confirmed by the experimen...