When voters with high political knowledge change their votes, it is usually to ideologically similar parties

Electoral volatility has been much discussed of late, with the rise of small parties leading to switches from across the political spectrum. While much research has taken place into the extent of vote switching, rather less has taken place into the ideological ‘distance’ between the parties that are switched between. Ruth Dassonneville and Yves Dejaeghere have done so, and found that voters with a higher level of political knowledge and sophistication switch to parties with a similar ideological profile to the ones they desert. 

Ukip voters, who may ideologically be next closest to the Conservative Party (Credit: Roger Marks, CC BY SA ND 2.0)

Ukip voters, who may ideologically be next closest to the Conservative Party (Credit: Roger Marks, CC BY SA ND 2.0)

Looking at the shifts in vote shares between one election and another, a number of scholars have indicated that electoral volatility is rising. This was challenging for the classical theories of voting behavior that stress the importance of social cleavages and hence stability. In defense of cleavage theories, it is generally assumed that voters who switch to an ideologically close party are driven by rational considerations. Volatile voters are still thought to be bounded by ideological considerations and to make a structured choice. Additionally, switching to parties within an ideological block is often interpreted as driven by strategic consideration. Voters switching between blocks, on the other hand, do not seem to be taking ideology into account when voting. In aggregate-level as well as in individual-level research, scholars therefore regularly distinguish between voters who change parties within an ideological block on the one hand and voters changing blocks on the other. Scholars have shown that most switching does occur within ideological blocks of parties. Clearly, when looking at volatility, degrees of switching have to be taken into account.

Although it is an old issue in the field of electoral behavior, the question whether political sophistication increases or decreases vote switching is still unclear and intensely debated. We aim to gain new insights in the causal link between political sophistication and party switching by explicitly taking into account the aspect of ideological distance.

Political sophistication: Stimulus or restraint of party switching?

Even though it seems obvious to take into account whether voters switch to ideologically close or distant parties when investigating the link between political sophistication and volatility, this has only rarely been done. Both Lachat and Kuhn do distinguish between within- and between-block switching in the German and/or Swiss context, but neither of them posits a different hypothesis for the effect of political sophistication on volatility for the two types of volatility. A non-linear relationship is by both authors argued to be expected for within-block switching as well as for between-block switching.

Looking at their results for switching from one election to another, a strong curvilinear pattern, with the middle sophisticated voters most likely to switch, can indeed be observed when switching between party blocks is considered. For within-block switching, the evidence does not suggest a curvilinear pattern, however. These contradictory results for both types of volatility have been interpreted as surprising and have led Kuhn to assert that her results: “reveal however also the necessity to further reflect and investigate on the effect between political sophistication, particularly on the striking differences of between- and within-block changes.”

Trying to explain the high likelihood of within-block switching among the high sophisticated in Germany, Lachat refers to the practice of strategic voting in the German electoral context. Strategic considerations are expected to be cognitively quite demanding and cues given by parties to enhance strategic voting as well are most likely to be perceived by political experts, hence the high presence of within-block switching among the high sophisticated. Additionally, Lachat indicates the asymmetry in political information between large and small parties as a source for high sophisticated voters’ high likelihood of within-block switching.

Given the relative scarcity of information on smaller parties, only high sophisticated voters can be expected to be exposed to this information and to subsequently switch to a small party within ‘their’ block. While not excluding the impact of strategic voting and information, we suggest that the ideological distance of parties within a party block is crucial in this regard. High politically sophisticated voters have previously been found to have better developed political attitudes than political novices. Therefore, we expect that ideology is an important restraint for high politically sophisticated voters who switch parties, which can explain their high rate of within-block switching. We test the straightforward hypothesis that as a voter’s level of political sophistication increases, the ideological distance bridged from one election to another is smaller.

Our Hypothesis is that the higher a voter’s level of political sophistication, the smaller the ideological distance she bridges from one election to another.


For testing our hypothesis, we make use of the data provided by the Comparative Study of Electoral Systems (CSES)-project. Given that we are focusing on volatility at an individual level, we are confined to those surveys within the project that included a recall question on previous voting behavior. Such a question was included from the second module of the CSES-project onwards, therefore the data used for the current analyses are from the second and third modules of CSES


For investigating the distance of switching we present two models. Model 1 only includes the main effect of political knowledge. In Model 2 we test for a curvilinear effect by including both the main and the squared effect of political knowledge. There are no significant differences between male and female voters or between voters holding a college degree and voters without a college degree. The variables capturing voters’ sense of political disaffection are negative and significant. As voters are more satisfied with democracy and have a higher sense of political efficacy, they bridge a significantly smaller ideological distance. The effect of closeness to a party is strong and significant and indicates that voters identifying with a political party are more ideologically restricted in their vote choices. The ideological distance to the closest party then, similarly as to what we observed for party switching, is not a significant predictor of the distance bridged.

Contrary to what can be observed for switching as such, when taking into account the distance of party switching, the effect of political sophistication on switching seems to be linear. The statistical fit for both models is about the same, but when only including the main effect of knowledge we find a negative effect of knowledge on the distance bridged. When including both the main and the squared effect, on the other hand, none of them reaches a conventional level of statistical significance.


Whether voters are political novices or political experts not only affects their probability of switching parties, it also has an impact on the ideological distance bridged. The higher voters’ level of knowledge about politics, the more ideologically constrained the vote choice of these voters. This implies that if a political expert switches at all, it will be to a party that is ideologically very close to the party previously voted for. As a consequence, if one is interested in the effect of political sophistication on electoral volatility, one should not distinguish within- from between-block switching. Voters switching between parties of different ideological blocks and voters switching within a block of parties are most likely to be different in terms of levels of political sophistication. As a result, investigating both groups separately would blur the effect that political sophistication has on voters’ likelihood of switching parties in general.

Note: This post is a summary, of ‘Bridging the ideological space: A cross-national analysis of the distance of party switching’ that is forthcoming in the European Journal of Political Research. It represents the views of the authors and not those of Democratic Audit or the LSE. Please read our comments policy before posting. The shortened URL for this post is: https://buff.ly/1lxRqVJ

ruth_dassonneville_bigRuth Dassonneville is a PhD fellow of the Research Foundation – Flanders (FWO). Her research is on electoral volatility in Western Europe and has specific attention for changes in voting behavior over the past decades. She has previously published on this topic in Acta Politica, German Politics, Party Politics and Electoral Studies.


photoYves Dejaeghere is senior researcher and lecturer at the University of Antwerp and is affiliated with the Centre for Citizenship and Democracy at the KULeuven as a lecturer on political communication and social movements. He was previously also a lecturer at KULAK and at the Université Catholique de Lille (France). From May till October 2012 he was a guest researcher at the department of Sociology of the University of Oxford. He works on topics of political socialisation, contemporary forms of citizenship and electoral behaviour.


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