Patterns of intraparty competition in open-list & SNTV systems

Two electoral systems that use “nontransferable preference votes” are commonly used: single nontransferable vote (SNTV) and open-list proportional representation (OLPR). Both systems promote intraparty competition by vote-seeking candidates, but differ on the extent to which the incentives of individual candidates and collective seat-maximizing parties are aligned, or not. We develop “logical models” of expected vote shares of parties' first and last winners, and test (and confirm) these models using “symmetric regression” on an original data set drawn from over 2000 party-district observations in nine countries. The analysis helps bring us closer to an understanding of the relatively neglected “intraparty dimension” of representation, and allows us to offer some modest suggestions for improving systems of nontransferable preference votes.