This is a time when more and more social scientists are becoming concerned about making their useful for public policy makers and policy makers are displaying spurts of well publicized concern about the usefulness of the social science that government funds support. There is mutual interest in whether social science intended to influence policy is actually used but before that important issue can profitably be addressed it is essential to understand what using actually means. A review of the literature reveals that a diverse array of meanings is attached to the term. Much of the ambiguity in the discussion of research utilization-and conflicting interpretations of its prevalence and the routes by which it occurs-derives from conceptual confusion. If we are to gain a better understanding of the extent to which social science has affected public policy in the past and learn how to make its contribution more effective in the future we need to clarify the concept. Upon examination the use of social science in the sphere of public policy is an extraordinarily complex phenomenon. Authors who have addressed the subject have evoked diverse images of the processes and purposes of utilization. Here I will try to extract seven different meanings that have been associated with the concept. (excerpt)