QRE is used by experimental economists to estimate the distribution of utility functions in populations of real people placed in situations modeled as games.

Given the unresolved complex relationship between learning theory and game theory, the reasoning above might seem to imply that game theory can never be applied to situations involving human players that are novel for them. Fortunately, however, we face no such impasse. In a pair of influential papers in the mid-to-late 1990s, McKelvey and Palfrey (1995, 1998) developed the solution concept of quantal response equilibrium (QRE). QRE is not a refinement of NE, in the sense of being a philosophi