Measuring district-level partisanship with implications for the analysis of US elections

Studies of American politics, particularly legislative politics, rely heavily on measures of the partisanship of a district. We develop a measurement model for this concept, estimating partisanship in the absence of election-specific, short-term factors, such as national-level swings specific to particular elections, incumbency advantage, and home-state effects in presidential elections. We estimate the measurement model using electoral returns and district-level demographic characteristics spanning five decades (1952-2000), letting its assess how the distribution of district partisanship has changed over time, in response to population movements and redistricting, particularly via the creation of majority-minority districts. We validate the partisanship measure with an analysis of congressional roll-call data. The model is easily extended to incorporate other indicators of district partisanship, such as survey data.