Split-ticket patterns in mixed-member proportional election systems: Estimates and analyses of their spatial variation at the German federal election, 1998

Mixed-member proportional election systems give voters two choices - one for a party candidate in a first-past-the-post single-member constituency election and the other for a party list in a multi-member constituency. Some will vote a straight ticket (i.e. vote for the same party at each contest); others may vote a split-ticket. Although such an electoral system has been operating in Germany since 1953, very little work has been done on variations between constituencies in either the volume of split-ticket voting or the direction of the switching involved. Using an entropy-maximizing method, this article reports estimates of the pattern of straight-ticket and split-ticket voting in each of Germany's 328 constituencies at the 1998 federal elections. Analyses of the variations show that the patterns are consistent with patterns of party strength at the constituency level: the stronger a party's performance at the 1994 election, the better its ability to retain the support of straight-ticket voters in 1998, to limit the out-flows of split-ticket voters, and to attract split-ticket voters who supported another party in the list contest.