Is the party system affected by booms and busts? Not very much

The literature on party system fragmentation emphasizes how political institutions and social cleavages shape the long-term development of the party system, but short-term swings in economic performance could change the level of electoral fragmentation by affecting the concentration of the vote in the executive. Time series data from presidential elections in 59 countries and from district-level legislative election contests in 22 countries show that a growing economy is negatively associated with the effective number of parties winning votes: a strong economy leads to a slight reduction in fragmentation as the ruling party consolidates its rule while a weak economy tends to disperse votes among alternatives to it. But the effect of economic performance relative to political institutions and the incumbency advantage is at the margins. The modest size of this effect should remind scholars of the limits of the economy as an overall driver of voter choice. Keywords: Economic Voting, Party System Fragmentation, Duverger's Hypothesis.