Abstract
This paper offers a new electoral geography perspective on two stylized facts that do not fit easily with our current understanding of the implications of electoral rules for electoral politics and social policy: (1) proportional representation (PR) electoral rules are not always associated with more generous social spending. In some cases, we observe comparatively high levels of social spending in majoritarian single-member district (SMD) systems. (2) Contrary to our theoretical expectations, national two-party competition occurs rarely, even under SMD rules. Here, I demonstrate the importance of electoral geography through a series of analytic examples that are based on a simple model of electoral politics, and in which all possible combinations of electoral boundaries, rules, and voter locations are manipulated.
1. Introduction
This paper offers some formal theoretic evidence of the importance of electoral geography, and accounts for two stylized facts that do not fit easily with our current understanding of the implications of electoral rules:
Proportional representation (PR) electoral rules are not always associated with more generous social spending. In some cases, we observe comparatively high levels of social spending in majoritarian single-member district (SMD) systems. 1
National two-party competition rarely occurs, even under SMD rules. 2
Previous studies of redistributive politics have focused on the incentive structures created by either pure SMD or nationwide PR, and assume either fully integrated populations or populations that are perfectly segregated across districts (e.g. Iversen and Soskice, 2006; Lizzeri and Persisco, 2003; Persson and Tabellini, 2000; Persson et al., 2007). My analysis considers, at least conceptually, all possible combinations of lines, rules, and locations. Once one does that, the effect of moving from SMD to various kinds of PR (not just nationwide) can have quite diverse impacts on a group’s representation in the legislature. Here, I focus on the geographic distribution of low-income citizens and show that the usual relationship between electoral rules and social spending (that PR leads to more generous social spending) holds only when electoral geography is ignored. I show that, under some conditions, the poor will do better when elections are contested in SMDs, compared to PR rules.
2. Electoral politics and redistribution
Following Iversen and Soskice (2006; see also Acemoglu and Robinson, 2006; Persson and Tabellini, 2000), this section presents a standard group-based model of redistributive politics. 3 Here, redistributive politics takes the form of a three-stage game: First, during a campaign period, parties commit to redistributive policies in anticipation of voter decision-making. Then, in a second stage, elections are held, and some citizens vote. In this analysis, voters cast a single (closed party-list) ballot, and seats are allocated to parties according to established SMD or multi-member district (MMD) PR electoral rules. Finally, governments are formed, and the governing party or coalition implements its most preferred policies perfectly. This simple model provides the basis of formal analytic examples that will illustrate the importance of electoral geography. Before introducing different income and legislative seat distributions, the next few sections will make explicit assumptions about voter preferences and party strategies.
2.1. Citizens
Suppose that there are three types of citizen, defined by their income: there are low-income citizens (L), middle-income citizens (M), and high-income citizens (H). Let yj denote earnings income, and assume
Then, let each citizen’s indirect utility function be determined by their level of post-tax and transfer income:
Here, Tj reports lump-sum taxes assessed for each citizen type, and Bj reports any benefits that are distributed to citizens of type j; pj reports the net benefits of redistributive policy.
2.2. Parties and election campaigns
Parties are groups of citizens who together stand for election: party
This taxation capacity implicitly limits fully redistributive policies that may undermine earnings incentives. Nevertheless, by assumption, this taxation capacity increases with earnings.
Notice that equation (4) also implies that the society’s taxation capacity is equal to the taxation capacities of M and H. Therefore, a balanced budget constraint requires that the total amount to be redistributed is equal to the sum
Finally, by assumption, policies are redistributive and weakly non-regressive:
Iversen and Soskice (2006) note that this non-regressivity assumption is weaker than similar assumptions typically made in formal analysis of tax-and-transfer policies (Meltzer and Richard, 1981; Romer, 1975), and is empirically well supported in contemporary democracies (see e.g. Milanovic, 2000). As we shall see, this assumption imposes important constraints on otherwise potentially viable coalitions: a governing coalition of low- and high-income voters, for example, is rarely viable.
2.3. Forming government
Parties that can form the government independently will implement their most preferred policies. Let the policy vectors
That is, low-income citizens would tax middle- and high-income citizens at their full taxable capacities, and distribute benefits exclusively among low-income citizens. Middle-income citizens would most prefer to tax the high-income citizens at their capacity, without bearing any tax burden themselves; the non-regressivity constraint implies that middle-income citizens will do best when they split their tax receipts equally with the poor. Finally, no redistribution is the optimal outcome for high-income citizens. 4
When no party, however, is elected to the majority of seats in the legislature (regardless of the electoral rules) parties enter into negotiations to form a coalition government, which will then implement a compromise policy. Here, following Iversen and Soskice (2006), party negotiations are approximated by a Rubinstein bargaining process, between equally impatient parties (i.e. discount rates are set equal to one). The resulting coalition policies are summarized by the policy vectors,
As Iversen and Soskice (2006, Proposition II) demonstrate, these cases are exhaustive: given the opportunity to be the formateur, high-income citizens strictly prefer a coalition with middle-income citizens over a coalition with low-income citizens. However, when
2.4. Equilibrium criteria
This analysis assumes that parties and voters have complete information about the outcome of the election. Thus, if citizens and parties know the distribution of types within the electorate, the electoral rules that govern the distribution of seats within districts, and the policies that will be implemented by the parties and coalitions that form the government, then sub-game perfection with weakly undominated voting strategies is the appropriate equilibrium concept. Here, sub-game perfection implies that the policies proposed by parties are optimal given anticipated voter decision-making. Weak dominance requires that voters do not vote for a party (i.e. voting by type), when ballots cast in favor of a different party (‘strategic voting’) can result in a more favorable redistributive policy.
Notice that policy outcomes are fully anticipated by the governing party or coalition: In equilibrium, parties can form the government independently will implement their most preferred policies. Otherwise, the formateur (here, the party with the largest seat share) will enter into coalition with their most preferred coalition partner, and together they will implement the compromise policies described in equation (8). As a consequence, parties have no incentive to moderate their policies during the campaign period because voters will not see these promises as credible. Voter strategies, therefore, can be summarized with regards to their expectation about which party or coalition will form the government, and the policies they will implement (see Table 1).
Citizen voting strategies. This reports citizen voting rules for each group of citizens, in anticipation of majority governments formed by each party and each viable coalition, when each income groups vote sincerely. In each coalition
Table 1 reports how citizens, with complete knowledge of the electoral geography of their societies (that is, the distribution of citizen types and legislative seats) will vote in anticipation of the governing party or coalition, listed in the first column. The cells of the table report citizen voting strategies as a result of these expectations. For example, reading across the top row of Table 1, in expectation of a majority government formed by the low-income citizens’ party (
2.5. Summary
In this section, I have presented a nearly institutions-free model of redistributive politics: only the timing of elections, relative to the implementation of policy, structures the decision-making of voters and parties. The next section of this discussion will introduce two innovations to the standard analysis of redistributive politics that have important implications for our understanding of how electoral rules contribute to social policy outcomes: turnout bias and electoral geography.
3. Turnout bias and electoral geography
Suppose that low-income, middle-income, and high-income citizens comprise equal proportions of the population. Further, suppose that there are some factors, exogenous to electoral competition, that prevent some citizens from voting. Assume that low-income citizens feel the effects of these factors more frequently than middle-income citizens, who themselves are less likely to turn out than high-income citizens. 6 Then, let π i define the proportion of voters of type i in the electorate: 7
In this analysis, this ‘turnout bias’ is minimal and this assumption will operate as a tie-breaking rule. 8 Nevertheless, as we shall see, the implications of even minimal turnout bias are especially important in plurality elections contested in heterogeneous districts. 9
To introduce electoral geography, I maintain the national distribution of citizen types within the population (each comprising one third) and manipulate their distribution across different regions of a hypothetical country. Specifically, imagine three countries in which the population is distributed across three types of region that are distinguished by their population density: there is an ‘urban’ high-density region, a ‘rural’ low-density region, and a suburban medium- or mixed-density region, with the composition of each region defined by
Thus, the high-income voters live predominantly in urban districts (denoted by the superscript U), areas surrounding cities (‘suburban districts’, S) are comprised of mainly middle-income and low-income citizens, and the low-income voters are the largest group of rural districts (R). 11
As in the case of Country R, urban areas in Country U are comprised mainly of high- and low-income citizens, although now low-income citizens form the largest plurality in urban areas. Also, in contrast to Country R, non-urban areas are composed of mainly high- and middle-income citizens. 12
In each of these countries, the population is spread across density regions in approximately equal proportions, but with somewhat more citizens living in ‘suburban’ or medium-density areas, and slightly fewer citizens living in rural or low-density areas. Although the terms urban, rural, and suburban provide a useful framework for this analysis, they are not intended convey any substantive meaning beyond population density.
Of course, the geographic distribution of voter types is only one component of electoral geography. Legislative seats must also be distributed across electoral districts. Figure 1 depicts the geographic distribution of voters, with each labeled area corresponding to 1/15 of the population. Thus, in each country, as described just above, one-third of the population resides in urban areas, denoted by

District structure under different electoral rules: the structure of the electoral districts of Assemblies S (denoted by dotted lines), N (denoted by the dashed line), and V (denoted by solid lines).
Note that assemblies S, N, and V vary on two dimensions: first, the assemblies vary in the average number of legislators elected in each district. Second, the assemblies differ in the variance of legislators elected across districts (see Monroe and Rose, 2002). Usually, analysis of the relationship between electoral rules and redistributive policy has focused on a comparison of assemblies S and N. However, as will become clear shortly, when the geographic distribution of voter types is taken into account, the important differences in the construction of MMDs in assemblies N and V can generate divergent redistributive outcomes.
4. Analyzing the implications of electoral geography for redistributive policy outcomes
Given a particular geographic distribution of income, which electoral rules generate the most redistribution? This rephrasing of the motivating research question (‘what are the implications of electoral geography for social policy?’) provides a framework for the analysis of policy outcomes for each country, and under different sets of electoral rules. This section offers a general discussion of the four outcomes identified for the set of nine cases (three countries, three sets of electoral rules), and leaves the technical details of the equilibrium analysis for Appendix A.
The earlier discussion of voter strategies anticipates the set of outcomes observed across this set of analytic examples. Governments are formed by:
The low-income citizens’ party,
A coalition of the low- and middle-income citizens’ parties,
The middle-income citizens’ party,
The high-income citizens’ party,
To examine the comparative implications of electoral geography more completely, it is helpful to suppose that cross-national differences can be summarized by an electoral concentration ratio,

First, most previous analyses compare policy outcomes under different electoral rules: Assembly V (solid line), Assembly N (dotted line), and Assembly S (dashed line), under different assumptions about the geographic distribution of income groups. The horizontal axes report the ratio of rural low-income citizens to urban low-income citizens. The case labeled ‘R’, for example, corresponds to the case of ‘rural poverty’, or when low-income citizens are over-represented in rural districts.
Notice that the important modifying effect of the geographic concentration of low-income citizens is quite clear: first, that much of the previous literature compares policy outcomes in national MMDs and SMDs, which correspond to points
The summary presented in Figure 2 draws attention to several further empirical implications resulting from this analysis. Here, I concentrate on three implications that are unanticipated by previous work: first, when low-income citizens are geographically concentrated, a change from MMD to SMD electoral rules can create incentives for more generous redistributive spending. Similarly, in systems with SMD rules, redistributive policy ought to be more generous in those systems where low-income citizens are more frequently pivotal in the allocation of seats. Finally, in systems in which district magnitude varies with population density, those countries in which low-income citizens are over-represented in rural areas ought to be characterized by more generous redistributive policy than in other countries with varying district magnitude electoral rules.
5. The implications of electoral geography for party competition
In a very straightforward modification of the model presented above, we can evaluate the implications of electoral geography for the structure of party competition under each set of electoral rules. Suppose, for example, that parties must bare (fixed and equal) costs associated with contesting the election, but that these costs are fully covered by the benefits of having even a single cast in its favor (e.g. perhaps achieving ‘official party status’). Under which conditions will the low-income people’s party,
The geographic distribution of income groups, and especially low-income voters, importantly determines the structure of party competition. When elections are contested under varying-MMD rules (Assembly V), and low-income voters are concentrated in either rural or urban areas, the low-income party will face incentives to contest the election; these incentives are absent when there is no geographic concentration of low-income voters. The geographic concentration of low-income voters in either rural or urban areas creates incentives for the low-income people’s party to contest the election even when elections are contested under SMD rules. This result, of course, contradicts Duverger’s law, but is consistent with much of the empirical analysis of party competition under SMD rules (see e.g. Gudgin and Taylor, 1979; Johnston and Pattie, 2006).
Remember, however, that when elections are contested in perfectly heterogenous districts (Country E), under SMD (or varying-MMD) rules, low-income voters will vote strategically for the party that represents the preferences of middle-income voters best,
6. Caveats
Beyond the imagined legislative district structures, this analysis makes several assumptions that are especially important for understanding the implications of the series of formal analytic examples.
Now suppose, instead, that rates of voter turnout decreased with income, and low-income voters outnumbered middle and high-income voters in the electorate. Again, only elections contested in Country E are affected. Notice, however, that low-income voters can expect policy outcomes that are no more generous than the original results, in which the government was formed by the party that represents the interests of middle-income citizens. Now, middle-income citizens face incentives to vote strategically for the party that represents the interests of high-income citizens (rather than suffer a government formed by the low-income people’s party). As long as low-income citizens do not comprise more than half of the electorate, the high-income peoples’ party will form the government, and implement its most preferred policy. If there are costs to contesting the election, again, electoral competition will be dominated by two parties: in this case, which is similar to what Iversen and Soskice (2006) find for SMD elections, the low- and high-income peoples’ parties will stand for election, and the middle-income voters will be pivotal. Notice, however, that this outcome does not require an explicit electoral coalition between middle-income, and low- and high-income citizens, and no assumption of two-party competition under SMD rules is necessary.
7. Conclusion
Using a series of formal analytic examples, based on a simple model of electoral politics, this paper has explored some important implications of electoral geography and challenges two generally held conclusions about the relationship between electoral politics and social spending: first, SMD electoral rules can sometimes lead to social spending that is at least as generous as the social spending that results from PR rules. How, then, can the empirical relationship between MMD electoral rules and social spending be accounted for (e.g. Iversen and Soskice, 2006; Alesina and Glaeser, 2004; Persson and Tabellini, 2003)? What might this analysis suggest about the electoral geography of countries with MMD electoral rules? We ought to find few MMD countries in which low-income citizens are over-represented in urban districts. Similarly, when elections are contested under SMD rules, more generous social spending should be associated with systems with less equitable distributions of low-income voters.
With the incorporation of electoral geography, this paper also offers new insight to our understanding of party competition under SMD rules: when voters are not evenly distributed across electoral districts, we might reasonably expect multi-party competition under SMD electoral rules. In this analysis, two-party competition results only when there is an even distribution of voter types across electoral districts, and turnout bias undermines the equitable representation of low-income voters in the electorate. This creates incentives for low-income voters to vote strategically for the middle-income people’s party, but without creating incentives for the middle-income people’s party to be responsive to the poor.
Footnotes
Appendix. Equilibrium analysis
In the formal analytic examples that were presented in the main body of this discussion, equilibrium strategy profiles consist of a set of policy proposals, one for each party, and the voting decisions of each income group of voters. Voters know the geographic distribution of different income groups, and can fully anticipate which party or coalition will form the government and the policies they will implement. As a consequence, voters will either vote by type, or vote strategically for the party that will ensure an optimal policy outcome. With no ability to commit to modified policy proposals, parties will propose either their most preferred policy or the policy that will yield the coalition that is optimal from the perspective of the voters they represent.
Acknowledgements
Chris Achen, Gary Cox, Jim Fearon, Rob Franzese, Clayton Nall, Jonathan Rodden, and anonymous reviewers provided extremely helpful comments on this analysis. This research builds on work submitted as part of my dissertation research, completed for the University of Michigan, while in residence at the Center for the Study of Democratic Politics, at Princeton University (Jusko, 2008).
Funding
This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
