On the value of commitment

Joshua Letchford, Dmytro Korzhyk, Vincent Conitzer

Abstract: In game theory, it is well known that being able to commit to a strategy before other players move can be beneficial. In this paper, we analyze how much benefit a player can derive from commitment in various types of games, in a quantitative sense that is similar to concepts such as the value of mediation and the price of anarchy. Specifically, we introduce and study the value of pure commitment (the benefit of committing to a pure strategy), the value of mixed commitment (the benefit of committing to a mixed strategy), and the mixed versus pure commitment ratio (how much can be gained by committing to a mixed strategy rather than a pure one). In addition to theoretical results about how large these values are in the extreme case in various classes of games, we also give average-case results based on randomly drawn normal-form games.