This paper is concerned with understanding how social science research comes to influence legal decision makers. Part one suggests that three dimensions are important in understanding the probable utilization of social science knowledge. These are the identity of the user, whether or not the research is commissioned by a user and whether the research takes the form of a study or a synthesis. Whether research is basic or applied in its orientation is regarded as less important than the preceding considerations. Part two examines the ways in which social science research is actually used by administrative agencies and then asks whether those patterns that apply in administrative agencies are likely to be duplicated by courts. Judges in appellate courts, it is argued, treat social science research in much the same way as do policy makers in administrative agencies, which is to say that direct and dispositive uses are rare, but research may serve an enlightenment or strategic function. Trial decision makers, on the other hand, are often directly influenced by social science findings. The difference between the utilization of social science research at the trial and appellate levels are explained by structural consideration.