Partisan Bias in U.S. Congressional Elections, 1952-1996

Abstract

The Democratic Party held a majority of the seats in the House of Representatives from 1952 to 1994. During the same period, however, they did not demonstrate the same level of success in the Senate. What explains these differing levels of success in the two chambers of Congress? Here I explore the contribution of partisan bias to this discrepancy. Three separate measures of partisan bias (distributional, population, and turnout) are explained and calculated for each chamber for the elections from 1952 through 1996. These estimates of partisan bias are linked to the proportion of seats that the parties have controlled in both the House and the Senate. Results indicate that the Democrats reaped the benefits of bias in House elections (particularly turnout-related bias). Bias in the Senate, particularly distributional and population-related bias, favored the Republicans.