“…In epidemiology, which seeks to identify the causes of a disorder in a population, we first start descriptively by identifying the person, place, and time factors that link those with the disorder to those without such a disorder (Lilienfeld and Lilienfeld, 1980). From the perspective of prevention methodology, these same person, place, and time considerations play a fundamental roles in trial design (Brown and Liao, 1999;Brown et al, 2006Brown et al, , 2007a and analysis Bryk and Raudenbush, 1987;Goldstein, 2003;Hedeker and Gibbons, 1994;Muthén, 1997;Muthén and Shedden, 1999;Muthén et al, 2002;Raudenbush, 1997;Wang et al, 2005;Xu and Hedeker, 2001). Randomized trial designs have extended beyond those with individual level randomization to those that randomize at the level of the group or place (Brown and Liao, 1999;Brown et al, 2006;Donner and Klar, 2000;Murray, 1998;Raudenbush, 1997;Raudenbush and Liu, 2000;Seltzer, 2004).…”