“…Attempts to understand and characterize the college community and its dynamics offer the potential to aid in policy decisions and reduce the problems that arise from alcohol use. In this article, we introduce a mathematical model that treats the college community as a system where levels of drinking vary over time not only as a result of student characteristics (Weitzman et al, 2003b), social interactions (Harford et al, 2002;Reifman et al, 2006), and social norms (Borsari and Carey, 2001;Perkins et al, 1999) but also because of external factors related to the "wetness" of a particular campus (Harford et al, 2002;Scribner et al, 2008;Wechsler and Nelson, 2008;Weitzman et al, 2003a). System models have been developed for analyzing drug use in other areas, including tobacco (Levy et al, 2001(Levy et al, , 2002Tengs et al, 2004), alcohol (Gorman et al, 2006), cocaine (Caulkins et al, 2004;Everingham and Rydell, 1994;Homer, 1993;Rydell et al, 1996), and heroin (Caulkins et al, 2007).…”