EW aspects of political activities in the American states have attracted m~ the attention as has the level of competition between the Democratic and Republican parties. In the wake of V. O. Key's (1949 and 1956) classic works in the field of state party systems and elections, numerous scholars have proposed measures of interparty competition (e.g., ) while others have sought to determine the policy consequences of such competition (e.g., ). In comparison, much less effort has been devoted to the question of why the party systems in some states are more competitive than those in others; studies investigating the determinants of party systems generally point to the link between interparty competition and socioeconomic factors. Several recent studies have focused on changes in the nature and effects of interparty competition over time (Tucker 1982;Feigert 1985;Kenney and Rice 1985; Tucker and Herzik 1986).Absent from these studies, however, is a separate consideration of the various dimensions of an index of interparty competition. This paper explores this aspect of interparty competition by examining relationships among the components of the commonly used Ranney index. Interparty competition in the chambers of state legislatures and for the governorship are analyzed in an effort to enhance our understanding of state party systems.
MEASURING INTERPARTY COMPETITIONThe literature on American state politics is replete with measures of interparty competition. With an occasional exception, these measures are based on the percentage of elections won by parties, the frequency of turnover in party control of offices, the percent of votes or legislative seats won, or a combination of the above. Some studies include contests for both national and state offices while others restrict themselves to elections at one level or the other. Each basis for an interparty competition index has its strengths and weaknesses (Pfeiffer 1967: 457-62; Zody and Luttbeg 1968).