Electoral Systems, Party Systems, and Ideological Representation: An Analysis of Distortion in Western Democracies

The effects of party system features and election rules on ideological representation can be seen in parliamentary elections in Western democracies over a fifty-year period. “Distortion” is short-term representation failure—the distance between the median voter and the legislature or government immediately after the election. Electoral choice and left-right positions of parties (from the manifesto data) can be used to estimate median voter positions. The number of parties, party polarization, and the election rules all independently affect ideological distances. But party system polarization seems to be the predominate factor shaping distortion of governments' relationship with the median voter. Examining the effects of party systems under different election rules helps clarify the causal connections between legislative and government levels.