The present study sought to provide further evidence for the validity of a modified version of the Pleasant Events Schedule (PES; D. J. MacPhillamy & P.M. designed to measure substance-free and substance-related reinforcement. A sample of 134 young adults completed the modified PES along with measures of substance use and quality of life. The results extend previous research on the modified PES in 3 ways: (a) Information regarding the relationships between substance-related reinforcement and substance use are expanded to include substance-use frequency, quantity, and related negative consequences; (b) relationships between substance-free reinforcement and non-substance-related variables are established; and (c) the distinctiveness of the substance-free and substance-related reinforcement scores is demonstrated. The utility of reinforcement surveys in the study of substance use is discussed, with special emphasis placed on possible treatment implications.The behavioral choice perspective is a collection of operant-based research and theories used to explain the establishment of preferences among available reinforcers. Behavioral theories of choice have been applied to a broad range of behaviors, including the prediction of cigarette smoking, eating and physical activity, and drug and alcohol abuse (Bickel, DeGranpre, Higgins, & Hughes, 1990;DeGranpre & Bickel, 1996;Epstein, Bulik, Perkins, Caggiula, & Rodefer, 1991;Epstein, Smith, Vara, & Rodefer, 1991;Vuchinich & Tucker, 1983, 1988. When applied to psychoactive substance use, the behavioral choice perspective recognizes that a preference for substance use develops within a broader environmental context involving the availability or use of other competing substance-free reinforcers and their associated environmental constraints. The theory predicts that substance use and related behaviors increase when access to alternative reinforcers is constrained or limited and that consumption decreases when access to the substance itself is constrained (Vuchinich & Tucker, 1983). Reviews of the literature suggest that both predictions have been supported by numerous laboratory-based experimental studies (cf. Carroll, 1996;Griffiths et al., 1980;Vuchinich & Tucker, 1988). Vuchinich and Tucker (1996) pointed out that the application of the behavioral choice framework to research in the natural environment is still in the early stages and that important empirical and design issues need to be resolved. In basic experimental research on choice, the schedules of reinforcement associated with alternative activities can be easily manipulated, constraints on access to the alternatives are readily introduced, and the resulting changes in behavior can be precisely quantified. In contrast, conducting behavioral choice research in the natural environment poses a number of significant challenges. For example, constraints on important life activities in the natural environment (e.g., marital relations, employment) cannot be controlled by the experimenter. Moreover, the complexity...