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A Spatial Model of Electoral Platforms Elff, Martin Uploaded 07-01-2008 Keywords Parties party families electoral platforms party manifestos spatial models unobserved data latent trait models EM algorithm Monte Carlo integration Monte Carlo EM importance sampling SIR algorithm ideological dimensions Abstract The reconstruction of political positions of parties, candidates and governments has made considerable headway during the last decades, not the least due to the efforts of the Manifesto Research Group the and Comparative Manifestos Project, which compiled and published a data set on the electoral platforms of political parties from most major democracies for most of the post-war era. A central assumption underlying the coding of electoral platforms into quantitative data as done by the MRG/CMP is that parties take positions by selective emphases of policy objectives, which put their accomplishments in a most positive light (Budge 2001) or are representative for their current polital/ideological positions. Consequently, the MRG/CMP data consist of percentages of the respective manifesto texts that refer to various policy objectives. As a consequence both of this underlying assumption and of the structure of the CMP data, methods of classical multivariate analysis are not well suited to these data, due to the requirements to the data for an appropriate application of these methods (van der Brug 2001; Elff 2002). The paper offers an alternative method for reconstructing positions in political spaces based on latent trait modelling, which both reï¬?ects the assumptions underlying the coding of the texts and the peculiar structure of the data. Finally, the validity of the proposed method is demonstrated with respect to the average position of party families within reconstructed policy spaces. It turns out that communist, socialist, and social democrat parties differ clearly from â??bourgeoisâ?? parties with regards to their positions on an economic left/right dimension, while British and Scandinavian conservative parties can be distinguished from Christian democratic parties by their respective positions on a libertarian/authoritarian and a traditionalist/modernist dimension. Similarly, the typical political positions of green (or â??New Politicsâ??) parties can be distinguished from the positions of other party families.

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The Trouble with Tobit: A District-Level Sample Selection Model of Voting for Extreme Right Parties in Europe, 1980-2004 Bowyer, Benjamin Uploaded 07-07-2008 Keywords Tobit Heckman sample selection censored data aggregate data extreme right parties Abstract The growing electoral success of extreme right parties (ERPs) in many European countries has sparked academic interest in explaining variation in extreme right success. However, much of the extant research on the electoral success of extreme right parties suffers from at least two types of selection bias. The first involves the selection of cases and occurs when only those national elections that were contested by extreme right parties are included in the cross-national analysis. To address this problem, a growing number of scholars of ERP electoral support employ Tobit models to analyze national-level election results pooled across countries and election years. However, this approach conceals a second source of selection bias: ERPs are extremely selective about which election districts within a country they choose to contest. The correct specification of this process of self-selection requires the recognition of two fundamental points. First, the causal factors that determine whether an extreme right party contests an election are not identical to those that influence its share of the vote if it does appear on the ballot. Second, this decision about when and where to field candidates is one that is observable at the level of the election district. This paper argues that the appropriate way to model is as a Heckman sample selection model estimated at the level of electoral district. I present a preliminary analysis of a dataset that pools district-level election results for eighteen European countries from 1980-2004 (N=12,050), the results of which demonstrate the value of this approach.

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Balancing Competing Demands: Position-Taking and Election Proximity in the European Parliament Lindstaedt, Rene Slapin, Jonathan Vander Wielen, Ryan Uploaded 07-31-2009 Keywords Legislative Politics European Parliament Comparative Politics Bayesian IRT Parties Formal Theory Abstract Parties value unity, yet, members of parliament face competing demands, giving them incentives to deviate from the party. For members of the European Parliament (MEPs), these competing demands are national party and European party group pressures. Here, we look at how MEPs respond to those competing demands. We examine ideological shifts within a single parliamentary term to assess how European Parliament (EP) election proximity affects party group cohesion. Our formal model of legislative behavior with multiple principals yields the following hypothesis: When EP elections are proximate, national party delegations shift toward national party positions, thus weakening EP party group cohesion. For our empirical test, we analyze roll call data from the fifth EP (1999-2004) using Bayesian item response models. We find significant movement among national party delegations as EP elections approach, which is consistent with our theoretical model, but surprising given the existing literature on EP elections as second-order contests.

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Modeling Electoral Coordination: Voters, Parties and Legislative Lists in Uruguay Levin, Ines Katz, Gabriel Uploaded 04-20-2011 Keywords electoral coordination number of parties Bayesian estimation multilevel modeling strategic voting Abstract During each electoral period, the strategic interaction between voters and political elites determines the number of viable candidates in a district. In this paper, we implement a hierarchical seemingly unrelated regression model to explain electoral coordination at the district level in Uruguay as a function of district magnitude, previous electoral outcomes and electoral regime. Elections in this country are particularly useful to test for institutional effects on the coordination process due to the large variations in district magnitude, to the simultaneity of presidential and legislative races held under different rules, and to the reforms implemented during the period under consideration. We find that district magnitude and electoral history heuristics have substantial effects on the number of competing and voted-for parties and lists. Our modeling approach uncovers important interaction-effects between the demand and supply side of the political market that were often overlooked in previous research.

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The Vote-Stealing and Turnout Effects of Third-Party Candidates in U.S. Presidential Elections, 1968-1996 Lacy, Dean Burden, Barry C. Uploaded 03-03-2000 Keywords vote choice turnout third parties multinomial probit Abstract A multinomial probit model of electoral choice in the 1968, 1980, 1992, and 1996 U.S. presidential elections, estimated using data from the American National Election Studies, reveals similarities and differences in electoral support for George Wallace, John Anderson, and Ross Perot. Estimates from the models are used to simulate the outcomes of the elections in the absence of the third-party candidate and under full turnout. In three of the four elections, the third-party candidates stole more votes from the challengers than from the incumbents. Only in 1996 did the third-party candidate take more votes away from the incumbent than the challenger. None of the four third-party candidacies increased turnout by more than 2.3 percentage points, and Perot's 1996 candidacy had the smallest impact on turnout of all of the third-party candidacies. Under full turnout, the outcome of only one election - 1968 - may have changed. All four third-party candidates increase their vote share under full turnout, and Democratic candidates gain vote share under full turnout in all elections except 1980. The paper also describes a new method for estimating the error variances and covariances in an MNP model.

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Parties, Issue Spaces, and Voting: A Comparative Perspective Alvarez, R. Michael Nagler, Jonathan Willette, Jennifer R. Uploaded 04-20-1998 Keywords elections parties issues comparative Abstract An important property of any party system is the set of choices it presents to the electorate. In this paper we analyze the distribution of the parties in the multidimensional issue space, and introduce the notion of compactness of the party system. We show how compactness can be measured using standard survey items found on national election surveys. By measuring the spacing of the parties relative to the distribution of the voters, we are able to compute a metric-free measure of compactness of the party system. Comparing the compactness of party systems across countries allows us to determine the relative amount of issue choice afforded voters in different polities. We test the impact compactness of the party space has on voter choice in four countries: the United States, the Netherlands, Canada, and Great Britain. We demonstrate that the more compact the issue space on any issue, the less voters weight that issue in making their vote decision. Thus we provide evidence for theories of issue voting.

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The Number of Parties: New Evidence from Local Elections Benoit, Kenneth Uploaded 08-11-1998 Keywords electoral systems regression analysis Duverger political parties Hungary Abstract Theory: Duverger's ``Law'' concerning the structural and psychological consequences of electoral rules has been much studied in both single cases and in multinational samples, but these suffer from several common theoretical and empirical shortcomings that make their estimates suspect. Besides resort to experimental data, another solution is to select a carefully controlled election dataset where the precise nature of the processes generating the data is understood. Local elections provide a means to control social cleavages as well as to provide a potentially large number of observations. Hypotheses: The size of electoral districts, as well as the type of electoral formula, will influence the number of parties that compete, the concentration of support for these parties, and the number of parties that win seats, even when the elections are confined to one country at the subnational level. In addition, the greater number of observations should provide very precise estimates of these effects. Methods: Regression analysis of district magnitude with an interactive term characterizing rules as proportional or plurality. The data come from 8,377 Hungarian local elected bodies consisting of municipal councils, county councils, town councils, and mayors. Results: The results extend previous research on Duverger's effects, providing more precise estimates that may be compared directly to previous results. In addition, the analysis of rare multi-member plurality elections reveals a counter-intuitive result about candidate and party entry in response to these rules, suggesting several directions for future investigation of MMP rules.

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When Politics and Models Collide: Estimating Models of Multi-PartyElections Alvarez, R. Michael Nagler, Jonathan Uploaded 00-00-0000 Keywords elections parties probit logit multinomial logit model-specification spatial model multinomial probit discrete-choice Abstract Theory: The spatial model of elections can better be represented by using conditional logit than by multinomial logit. The spatial model, and random utility models in general, suffer from a failure to adequately consider the substitutability of candidates sharing similar or identical issue positions. Hypotheses: Multinomial logit is not much better than successive applications of binomial logit. Conditional logit allows for considering more interesting political questions than does multinomial logit. The spatial model may not correspond to voter decision-making in multiple-candidate settings. Multinomial probit allows for a relaxation of the IIA condition and this should improve estimates of the effect of adding or removing parties. Methods: Comparisons of binomial logit, multinomial logit, conditional logit, and multinomial probit on simulated data and survey data from a three-party election. Results: Multinomial logit offers almost no benefits over binomial logit. Conditional logit is capable of examining movements by parties, whereas multinomial logit is not. Multinomial probit performs better than conditional logit when considering the effects of altering the set of choices available to voters.

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Electoral Competition with Endogenous Voter Preferences Jackson, John Uploaded 00-00-0000 Keywords electoral competition simulation path dependence parties Abstract The spatial model of electoral competition first proposed by Anthony Downs and subsequently extended by many authors is a core part of formal political theory. It has been and is currently used to study a wide variety of electoral processes and political institutions and its properties under many alternative conditions are now well known. All of this work, however, maintains the assumption that voters' preferences are exogenously given and can be treated as fixed while studying the behavior of competing parties and candidates. This makes all the resulting predictions conditional on this assumption. Empirical studies of voter preferences, by contrast, have connected changes in preferences to the platforms and actions of the competing parties and candidates. The paper connects these two literatures by developing a model of electoral competition that makes preferences endogenous, meaning that they co-evolve with party platforms during the election process. The model, which has both an analytical and a simulation form, is explored to ascertain its implications for the existence of stable outcomes, for the ability to predict these outcomes based on initial conditions and assumptions about party behavior, and for its dynamic properties. The assumption of fixed preferences is treated as a special case of this general model, enabling comparisons of these implications for the two situations. The version with endogenous preferences exhibits path dependent properties, which makes it quite different from the more traditional model.