Published online by Cambridge University Press: 02 January 2018
The use of “group” as a unit of analysis has a long tradition in political science. Some proponents of this approach (Bentley, 1908; Hagan, 1966) define group in such a broad way as to simplify the study of politics little if any. An empirically more useful approach to the study of groups is that pursued by David Truman (1955), who concentrates his attention on interest groups. Although he never states that all of the politics of the United States can be understood through the study of interest groups, it is clear that Truman considers the study of such groups to be a central aspect and, in effect, hypothesizes that such would be the case in any political system. Whether this is in fact the case can be tested by cross-national studies. In one such study, Joseph La Palombara (1960) concluded that the important aspects of Italian politics are not explained satisfactorily by studying organized interest groups. This is in direct contradiction to Truman's implicit hypothesis, which would be refuted if numerous studies in other political systems concluded as La Palombara's did.