There are two important rules to patent races: minimal accomplishment necessary to receive the patent and the allocation of the innovation benefits. We study the optimal combination of these rules. A planner, who cannot distinguish between competing firms in a multistage innovation race, chooses the patent rules by maximizing either consumer or social surplus. We show that efficiency cost of prizes is a key consideration. Races are undesirable only when efficiency costs are low, firms are similar, and social surplus is maximized. Otherwise, the optimal policy involves a race of nontrivial duration to spur innovation and filter out inferior innovators.