Electoral System Change, Generations, Competitiveness and Turnout in New Zealand, 1963–2005

In 1996, New Zealand changed its electoral system from single-member plurality (SMP) to a Mixed Member Proportional (MMP) system. This article addresses the effects on turnout of electoral system change, generational differences and national and district-level competitiveness. Both theory and cross-sectional empirical evidence indicate that turnout should be higher after the change to MMP. Yet turnout has declined. Most of this turns out to be an effect of lag effects generated by longer-term trends of declining competition, and generational experiences. MMP has shifted the main focus of electoral competition from the district to the national level, with consequent changes in turnout distribution. Electoral boundary changes also have negative effects under MMP, and most MMP elections have taken place after an electoral redistribution.