The nature of party governance: Connecting conceptualization and measurement

Research on the policy consequences of partisan turnover in policy-making institutions in the U.S. states generally has found that parties have, at most, conditional effects. Yet many of these analyses have constructed the partisanship variable as if parties in state government were fully unified. This paper explores the results stemming from various measurement choices, namely measures implying complete unity and those derived from a conceptualization of parties as undisciplined. The analysis demonstrates that a strong relationship between the partisanship of state legislatures and policy outcomes emerges only when the indicators are based upon our substantive knowledge of parties in state government.