In the literature the outcome of contests is either interpreted as win probabilities or as shares of the prize. With this in mind, we examine two approaches to contest success functions. In the rst we analyze the implications of contestants' incomplete information concerning the 'type'of the contest administrator. While in the case of two contestants this approach can rationalize prominent contest success functions, we show that it runs into di¢ culties when there are more agents. Our second approach interprets contest success functions as sharing rules and establishes a connection to bargaining and claims problems which is independent of the number of contestants. Both approaches provide foundations for popular contest success functi...