Testing Game Theory in the Field: Swedish LUPI Lottery Games

Game theory is usually difficult to test in the field because predictions typically depend sensitively on features that are not controlled or observed. We conduct one such test using both laboratory and field data from the Swedish lowest unique positive integer (LUPI) game. In this game, players pick positive integers and whoever chooses the lowest unique number wins. Equilibrium predictions are derived assuming Poisson distributed population uncertainty. The field and lab data show similar patterns. Despite various deviations from equilibrium, there is a surprising degree of convergence toward equilibrium. Some deviations can be rationalized by a cognitive hierarchy model. (JEL C70, C93, D44, H27)