Which Parties Benefit from Open-List ballots?

In this section we consider reasons why a move from closed-list to open-list ballots might help some parties and hurt others. Our focus is on the role of intraparty disagreement. Although intraparty disagreement may be a liability for any party under either closed-list or open-list PR elections, we expect parties with more intraparty disagreement to attract more voters under open-list competition than under closed-list competition, particularly when ideologically proximate parties have low levels of intraparty disagreement. The logic behind this explanation applies whether we consider voters to be expressive or strategic.

Expressive Voters and Intraparty Disagreement

Suppose that voter behavior is described by the following two assumptions:

E.1 Voters are expressive, meaning that they vote for the party or candidate they find most attractive and do not consider how their vote is likely to affect policy outcomes.

E.2 Voters cast their vote in a closed-list system based on the attractiveness of the parties, whereas they vote in an open-list system based on the attractiveness of the candidates.

Under these two assumptions, it follows that list type affects a voter’s party choice when party X is the most attractive party under closed lists, while a candidate from party Y is the most attractive candidate under open lists.

An example clarifies how this might happen. Suppose that in a given setting the Green Party is associated with clear positions on both economic and environmental policy; the Socialist Party, by contrast, has a clear left-wing economic position but has substantial intraparty disagreement on environmental policy, with some Socialist candidates strongly pro-environment and others less so. In an election held under closed lists, a left-wing environmentalist voter may find herself torn between the two parties: the Socialist Party may be more attractive on economic grounds, but the Green Party is more attractive on environmental policy. Suppose that under closed lists she votes Green because she views environmental issues as more important. Now consider her vote choice under open lists. Because there are Socialist candidates who advocate strong pro-environment policies, our voter may choose to support a pro-environment Socialist candidate who shares her left-wing economic preferences. If so, the list type would have affected the voter’s party choice because even though the most appealing party under closed lists was the Greens, the most appealing candidate under open lists was a Socialist.Footnote ⁹ To be clear, the Socialists’ lack of unity on environmental policy is not per se an attraction; on the contrary, the party’s internal disagreement may on balance be a liability in both closed-list and open-list competition. Rather, given the party’s internal disagreement we expect it to be more successful under open lists than under closed lists because expressive voters may be drawn to the party by the opportunity to support particularly attractive individual candidates.

Figure 1 illustrates the argument in a simple spatial model. There are two parties, X and Y, each identified with its own position in two-dimensional space; within each party, three candidates occupy distinct positions near their party, though party Y’s candidates are more distinct from each other. Asked to choose between parties (as in closed-list competition), an expressive voter with an ideal point at a would choose party X, whose position is slightly closer to her own ideal point. Asked to choose among candidates, however, the same voter would choose y ₁. The situation corresponds to the example given above, where parties X and Y are the Greens and the Socialists, respectively and the horizontal and vertical dimensions are economic policy and environmental policy.

Fig. 1

Ballot type and party vote choice when intraparty disagreement varies across parties

Which Parties Have Intraparty Disagreement on Salient Issues?

The level of internal disagreement may vary across parties in a given system for many reasons. In any electoral system, there is a trade-off between a party’s ability to offer a variety of candidates who cater to disparate tastes and goals in the electorate, on the one hand, and its ability to present a coherent and unified party brand,Footnote ¹⁴ on the other hand.Footnote ¹⁵ There may also be tension between the interests of party leaders, who value a coherent party brand and the interests of candidates, who may seek to differentiate themselves from the party in order to cultivate a personal vote.Footnote ¹⁶ The way parties resolve these tensions is likely to depend in subtle ways on their history, leadership and internal governance.

It is also important to recognize that the level of internal disagreement often varies within parties across issues; thus the effect of ballot type on a party’s electoral support may depend on which issues are salient. To use the example from the previous section, the Socialist Party may benefit from a transition to open-list competition if environmental issues are particularly salient (assuming that the Socialists have more internal disagreement on environmental issues than the Greens), while the Green Party may benefit from the same transition if economic issues are particularly salient (assuming that the Greens have more internal disagreement on economic issues).

One case where there may be particularly clear differences in internal disagreement across parties is when a ‘niche party’ competes on a salient issue against mainstream parties. Niche parties tend to emphasize issues that cut across the main dimension(s) of political competition; typically, they are highly internally unified on these issues, which helps them appeal to their ‘ideological clienteles’Footnote ¹⁷ and form a party brand.Footnote ¹⁸ Mainstream parties, by contrast, sometimes struggle to define a position on the issues emphasized by niche parties, particularly during the period when the issue is rising in salience. For example, Green parties and anti-immigration parties in Europe compete on the basis of strong and internally unified positions on issues on which the mainstream parties are internally divided. We might expect a move from closed-list to open-list competition to be damaging to the niche party when the niche party’s issue is salient to voters.

The idea that ‘niche’ parties might do worse in open-list competition would seem to apply particularly well to the case of European Parliament elections, where Eurosceptic parties have recently captured substantial electoral support. Eurosceptic parties define themselves by their opposition to the current design and operation of the EU. They compete against mainstream parties that originate from – and mainly compete in – national politics on a variety of other issues; they tend to have positions on Europe that are less salient, more vague, more variable over time and more diverse within the party. Expert surveysFootnote ¹⁹ confirm this difference, showing that parties that place a high salience on European integration are significantly less likely to be viewed as internally conflicted on the issue.Footnote ²⁰ In open-list elections focused on the question of European integration, mainstream parties can field candidates representing the range of positions on Europe, which (following the logic outlined in the previous section) seems likely to undermine support for Eurosceptic parties.

This general pattern fits the specific case of European elections in Britain well. UKIP has recently risen to prominence as a strongly Eurosceptic party; the mainstream parties, by contrast, are characterized to various extents by internal disagreement on the question of European integration. Intraparty disagreement is most pronounced within the Conservative party, with Conservative Members of Parliament and Members of the European Parliament (MEPs) openly expressing Eurosceptic views that go well beyond the party line,Footnote ²¹ but elite dissent is also visible in the Labour PartyFootnote ²² and, to a lesser extent, among the traditionally strongly pro-Europe Liberal Democrats.Footnote ²³ Supporters of the major parties also express a variety of viewpoints toward European integration. We observe this in our own survey, as documented in Appendix Table S4: although respondents supporting Labour, the Greens and the Liberal Democrats show a clear pro-Europe tendency, a substantial minority in each party expresses opposition to European integration.

In conjunction with the analysis in the previous section, this variation in intraparty disagreement across parties suggests a prediction about the effects of changing EP elections in Britain from a closed-list to an open-list format. The salient issue in these elections is (and will likely continue to be) the UK’s role in the European Union. On this issue, UKIP is (and will likely continue to be) highly unified compared to other mainstream parties. As a result, we expect UKIP to suffer from the introduction of open-list competition as Eurosceptic voters take advantage of the opportunity to vote for Eurosceptic candidates from other parties.

The direct corollary is that the Conservatives, which is the closest party to UKIP on the left-right dimension of conflict, will gain the votes that are lost by UKIP when open-list competition is introduced.

In the next section we introduce the experiment we designed to test this hypothesis.

Experimental Design

Our experiment was embedded in a survey conducted by the research firm YouGov and fielded between 26 June and 5 July 2013. The survey was administered to a random sample of 9,096 panelists who are, according to YouGov, representative of British adults in terms of age, gender, social class and newspaper consumption. For all analyses below, we use probability weights provided by YouGov to weight the survey to the national profile of all adults aged eighteen or older.Footnote ²⁴

For the core of the survey experiment, we asked subjects to vote in a hypothetical election for EP. All subjects were shown a ballot listing three candidates from each of five parties (Conservative Party, Green Party, Labour Party, Liberal Democrats and UKIP).Footnote ²⁵ Half of the subjects (chosen at random) were shown a closed-list ballot and asked to pick a party; the other half were shown an open-list ballot and asked to pick a candidate. As discussed above, our principal interest is in how parties’ vote shares depended on ballot type.

As a general matter, ballot type could affect party vote choice only if voters have preferences not just between parties but also among the candidates within parties. Given that the candidates in our experiment are all fictional, any preferences that our survey respondents had among candidates could only come from information we provide. We thus had to think carefully about what information to provide. A first question involved how much information to provide about the candidates. Ideally, we wanted to provide candidate information similar to what a British voter might acquire during the several weeks of an election campaign, when (depending on campaign behavior, which may itself depend on ballot type)Footnote ²⁶ the voter may receive fliers from various candidates and parties, watch debates, read endorsements, etc. Unfortunately, such a large and nuanced amount of information could not realistically be communicated in the few seconds that survey respondents spent learning about fictional candidates for our experiment. Ultimately, we decided to provide a subset of respondents with limited but clear information about the candidates’ positions on Europe: in addition to a name (and thus gender) and party affiliation, each candidate was endorsed by a (fictional) pro-integration pressure group called ‘Britain in Europe’, a (fictional) anti-integration pressure group called ‘Britain Out of Europe’, or neither. Respondents received this information in two steps: first they were shown a screen explaining the endorsements and listing the endorsed candidates (as shown in Figure 2); on the next screen they were again shown the endorsements alongside the ballot as a kind of ‘voter guide’ (as shown in Figure 3).

Fig. 2

Endorsement information provided to respondents before voting

Fig. 3

Excerpts from closed-list and open-list ballots, including endorsement information Note: actual ballots (shown in Appendix Figures S7–S10) provide more detailed instructions and include candidates for all five parties.

A second question involved the nature of the endorsements we assigned to each party’s candidates. As discussed above, we argue that intraparty disagreements about European integration are likely in the major UK parties, but not in UKIP. Accordingly, for each of the non-UKIP parties (Green, Labour, Liberal Democrat, Conservative), we had one of the three candidates endorsed by the pro-Europe group, one endorsed by the anti-Europe group and one endorsed by neither. For UKIP, we assigned an anti-Europe endorsement to all three candidates. It is therefore through the provision of endorsement information that we incorporate our theoretical assumption about intraparty disagreement into our empirical design.Footnote ²⁷

In order to disentangle the effect of the ballot type from the effect of the information we provided to respondents, we designed the experiment as a two-by-two factorial design (highlighted in Table 1) in which ballot type (closed or open list) and endorsement information (provided or not provided) are independently randomly assigned. Thus roughly one-quarter of our respondents was given ballots like the one shown at the top of Figure 3 (treatment group C, in Table 1) and one-quarter was given ballots like the one shown at the bottom of Figure 3 (treatment group D, in Table 1). Another quarter (treatment group A) was given a closed-list ballot with no endorsement information and another quarter (treatment group B) was given an open-list ballot with no endorsement information. This design allows us to address two potential objections to the endorsement information we provided as part of our experiment.

Table 1

Design Table

Note: weighted sample sizes shown.

The first potential concern is about internal validity of the study: if we only showed the endorsement information to respondents who are also given an open-list ballot, then it would be impossible to disentangle the effect of the information we provide from the effect of the ballot itself.Footnote ²⁸ The second potential concern relates to the external validity of the study: if all respondents are shown this endorsement information and if this information is too divergent from the way in which voters typically think of the parties, then the ballot type effect we detect may be very different from the effect that would be seen if the ballot type were actually changed. The factorial design allows us to address both concerns. Clearly, because we can separately test the effects of the endorsement information and the ballot type, we can address the internal validity concern. The design also allows us to address the external validity concern by testing whether the provision of information per se affects party vote choice among respondents who are given a closed-list ballot. As we show below, it did not, which suggests that our endorsements reflect positions on Europe that are not too dissimilar from what voters might expect to see from each party.Footnote ²⁹

Another external validity objection could be raised, which is that the endorsement information was provided in a particularly heavy-handed way. Granted, such endorsements would never appear on an actual ballot paper; the information that voters receive about candidates would tend to be much more noisy and multi-dimensional. Yet voters in a real election would have weeks to process the information to which they may be exposed and they would be able to actively seek out the specific information that may be of use to them (for example, ‘Which Labour candidate is most pro-integration?’). It is also not unusual for voters facing complex ballots to be given voter guides by candidates and civil society groups. We view our information treatment as a compromise made necessary by the constraints of running a hypothetical election with survey respondents who have limited time to process new information.

Before we proceed to the results, we first check the balance of the respondents’ covariate distributions across the four treatment groups. As expected from a randomized treatment allocation, the tests show no sign of imbalance. More precisely, the p-values calculated from a joint F(3, N−df) test of no differences between the twenty-two covariate means (all measured pre-treatment) across the four treatment conditions follow the expected uniform distribution over the [0, 1] interval. Appendix Figure S11 plots the empirical distribution of the p-values from these balance tests against the theoretically expected uniform distribution:Footnote ³⁰ since all p-values are above the forty-five degree line, we can safely assume that randomization was successful. Appendix Table S5 shows the underlying covariate means and corresponding F-tests across the four treatment conditions.

Discussion and Conclusion

Which parties win and lose when a closed-list PR system (such as the one Britain uses to elect its MEPs) is changed to an open-list system? We used a simple framework to assess how such a change would affect parties with different levels of internal disagreement on salient issues; we conclude that whether we think of voters as expressive or strategic, a change from closed lists to open lists is likely to be more beneficial to parties that have relatively high levels of internal disagreement on salient issues. We carried out a survey experiment that assessed this prediction in the case of UK elections to the European Parliament, where the solidly Eurosceptic UKIP competes against mainstream parties that are more internally divided on European integration. We suggest that, just as UKIP lost support from the adoption of open lists in our experiment, niche parties (which mobilize on an issue that cuts across the main dimension of party competition) would likely lose support from the adoption of open lists in a broader set of circumstances.

It should be noted that our analysis only addresses the most direct and immediate effect of a move from closed-list to open-list PR. That is, we have shown how the effect of ballot type depends on existing intraparty disagreement, but we have not addressed the question of how ballot type would affect intraparty disagreement itself, or how parties would respond more broadly to the introduction of intraparty competition. By placing each party’s candidates in competition with each other, the open-list system is likely to encourage differentiation among candidates. For the reasons discussed above, a party whose candidates are more distinct from one another may attract voters from more unified parties in open-list competition; voters may, however, punish such a party for appearing incoherent and disorganized. Thus the implications of reform for parties’ electoral success become less clear when we consider that parties’ internal disagreement would likely respond to the ballot type and that this response will vary across parties. In this sense, additional observational studies should be carried out to assess the total effect of ballot type reforms in practice. Yet observational studies of electoral reforms face substantial obstacles not only because reforms are rare and endogenous, but also because it is difficult to explain how such a reform affects political outcomes given the many possible channels through which such effects might operate.

As discussed above, one clear challenge to the external validity of any experiment like ours is the difficulty of reproducing the relevant aspects of an electoral campaign within the constraints of a survey. In our case, it could be argued that our estimates exaggerate the true likely effects of a change in ballot type (even holding fixed intraparty disagreement) because our respondents are given unrealistically clear and stark information about candidates’ policy positions. To be sure, an official ballot would not include endorsement information from two opposing NGOs; in a real open-list campaign we would expect candidates to blur some policy differences and we would not expect most voters to know most candidates’ positions. (We might also expect UKIP to point out that voting for a Eurosceptic Conservative could end up giving a seat to a pro-Europe Conservative.) However, voters in a real election would have more time to process information and, given the chance to cast an open-list ballot for an individual candidate, they may be drawn into the drama of intraparty disputes, which would tend to increase the effect we measure. We look forward to future research, including observational studies of electoral reforms, that helps determine whether our estimates provide an upper bound of the actual effect. At any rate, even if the true effect were substantially smaller than our estimate it would still deserve attention: we estimate that with a swing half as large as the one we find in our experiment, the Conservatives would still have gained an additional four seats out of seventy-three UK wide.

The context on which we focus, where an insurgent anti-integrationist party competes against mainstream parties for seats in the EP, has clear analogs in other European countries. For example, the Alternative for Germany, the Front National in France and the Danish People’s Party all promote anti-integrationist policies that differentiate them from the main center-right parties in each country. Elections in these countries also take place under closed lists, but in recent years key figures have called for open lists to be adopted in all EP elections.Footnote ³⁸ While we should be cautious about applying the results of our experiment to other party systems, our analysis suggests that such a reform could noticeably boost mainstream parties in European elections and thus cause a substantial shift in the strength of party groups in the EP; the broader effects of introducing open-list elections on the policies pursued by the various parties remains for future research.