Using information from the Peruvian administrative consumer system from 1998 to 2010, the paper assesses hypotheses taken from selection theory in the context of legal disputes (Priest and Klein, The Journal of Legal Studies 13(1):1, 1984) and political science. Hypotheses from selection theory regarding the influence of plaintiff stakes, informational asymmetry and, to a lesser extent, litigation costs on both selection decisions and trial outcomes were confirmed. In addition, the results corroborate other implications of selection theory, such as the non-random nature of selection processes. However, no evidence has been found regarding the theory's prediction that the share of plaintiff victories at trial will converge to 50%. The results also show that in the Peruvian consumer protection system, plaintiffs win more often than do defendants, suggesting the pre-eminence of pro-consumer trial standards over other factors. Moreover, the evidence confirms the hypotheses taken from "party capability theory" (Galanter, Law & Society Review 9(1):95-160, 1974) regarding the influence of litigant characteristics on consumer protection legal outcomes. Finally, the results also demonstrate the relevance of ideological and attitudinal factors as determinants of consumer administrative trial decisions. © 2014 Springer Science+Business Media New York.