ELECTORAL SYSTEMS AND VOTER TURNOUT: New theoretical research on who benefits

In societies where there is a strong minority – perhaps the so-called ''1%'' – that stacks the deck against the majority, a more proportional electoral system will better protect the interests of the majority. But if the electorate consists of citizens who are similar in terms of electoral benefits and voting costs, then majority rule generates higher turnout than other voting systems. These are among the findings of theoretical research by Dr Melis Kartal, published in the September 2015 Economic Journal.

Voter turnout has become an increasingly prominent issue as the number of people voting has been in steady decline in recent decades. Many people deem high voter turnout to be an essential part of the democratic ideal, which has led to ''get out the vote'' campaigns to increase electoral participation in many countries. Some also argue that using a particular electoral system can boost turnout.

From a scientific point of view, it is not obvious whether increased turnout or changing the electoral system to encourage turnout makes society as a whole better off. After all, it is the relative turnout of the competing parties that counts in the electoral battle, not the overall turnout.

Indeed, the mathematical analysis of voting in the new study establishes that higher turnout does not produce a net benefit to society if citizens are similar in terms of electoral benefits and voting costs. In such an electorate, majority rule generates higher turnout than other more proportional electoral systems – and yet every electoral system turns out to be equivalent in terms of overall benefits to society.

This is because in a (perhaps, unequally) divided but otherwise homogeneous electorate, competing groups put up an equally strong fight, which results in a very close election regardless of the electoral system. Put differently, turnout is relatively equally split across competing parties. Thus, the overall level of turnout is irrelevant and society benefits equally across different electoral systems.

This result relies on the homogeneity of the electorate. Dropping this assumption breaks the equivalence of electoral systems. Preserving similarity in every dimension but the cost of voting makes majority rule superior. But this result can reverse if heterogeneity is allowed for in both voting costs and electoral benefits.

For example, proportional representation performs clearly better than majority rule if there is a powerful minority group with large stakes in the electoral process. In particular, proportional representation protects the majority against a ''tyranny of the minority'', which majority rule fails to prevent.

The assumption about the existence of a powerful minority within the electorate is not far-fetched. The so-called ''1%'', for example, has become a part of both academic and public discourse as a term that represents an influential and wealthy minority that dominates political and economic decision-making.

Melis Kartal comments:

''When there is a strong minority that stacks the deck against a majority, it is beneficial to use more proportional systems to shield the majority interests.

''Overall, my results indicate that there is a very subtle relation among proportionality, turnout and overall benefits to society that depends on the precise characteristics of the electorate.''

 ''A Comparative Welfare Analysis of Electoral Systems with Endogenous Turnout'' by Melis Kartal is published in the September 2015 issue of the Economic Journal. Melis Kartal is at the University of Vienna.