Published Research

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Fernandes Jorge, Yakter Alon, Shomer Yael and Put Gert-Jan. “The Electoral Implications of Legislative Candidate Selection Democratization”, British Journal of Political Science, Forthcoming [IF 5.7; 16/322, Q1 top 5%]

This study investigates whether political parties benefit electorally from democratizing their candidate selection processes—such as introducing primaries or giving more influence to party members and voters. While inclusive selection procedures are often promoted as tools for enhancing legitimacy, transparency, and responsiveness, the paper argues that they do not meaningfully improve a party’s electoral performance. Drawing on a large-scale comparative analysis of 34 democracies from 1970 to 2019 and a preregistered conjoint experiment in France, Israel, and Sweden, the findings reveal a consistent pattern: although voters say they prefer more democratic candidate selection methods, they deprioritize them at the ballot box in favor of factors like ideological proximity and female representation. By combining observational and experimental approaches, the paper contributes to broader debates on party reform and democratic responsiveness. It demonstrates that institutional changes meant to signal openness and accountability may not translate into voter support unless they align with higher-salience electoral considerations. As such, party elites should not expect electoral rewards solely from procedural reforms, and scholars should continue to explore the multidimensional trade-offs voters make in complex political environments.

Shomer Yael, Tzalgov Eitan and Zur Roi. 2025. “The Crises of the Israeli Democracy: Introduction to a Research Topic”, Frontiers in Political Science, Forthcoming [IF 2.5; 90/322, Q2].

This paper introduces and contextualizes the democratic crisis in Israel through a scholarly lens. It introduces the broader research topic collection that critically examines Israel’s democratic crisis from various perspectives: institutional, legislative, judicial, and social. The paper seeks to summarize the collection of articles that were devoted to the question: were the judicial overhaul proposed in early 2023 by Israel’s newly elected right-wing government under Benjamin Netanyahu a mere institutional reform aiming at re-establishing the balance across the branches or was it  a far-reaching constitutional and regime coup?.    The article outlines the convergence of multiple developments over the past decade—including recurring elections, rising populism, growing polarization, alleged corruption, and institutional weakening to argue that the structural reform of the judiciary quickly emerged as a symbol of a more profound crisis of democratic governance, raising alarm among scholars, legal experts, and the broader public. Ultimately, the article emphasizes the need for continued academic engagement in analyzing the rapid transformations in Israeli democracy, both as a national case and as a lens for understanding global patterns of democratic backsliding.

Freund Amir and Yael Shomer. 2025. “National Leaders’ Gender effect on European Countries’ Performance during the COVID-19 Crisis”, European Journal of Political Research 64(2): pp. 864-871 [IF 5.3; 9/187, Q1 top 5%].

This study examines whether and how the gender of a national leader influenced countries’ performance in managing the COVID-19 pandemic. Drawing on data from 56 democracies over four waves of the pandemic, the research demonstrates that countries led by women consistently outperformed those led by men in terms of lower infection rates, mortality, and excess deaths—particularly in the first three waves. By combining a novel wave-alignment methodology with rigorous robustness checks, the authors isolate the effect of leader gender from confounding factors such as state capacity, healthcare system strength, or cultural context. The gendered performance gap narrowed in the fourth wave, where vaccination rates played a more dominant role, but female-led countries still maintained a relative advantage.   The article also probes the mechanisms driving this gap, offering empirical support for the roles of public trust and government effectiveness. Citizens in female-led countries consistently reported greater satisfaction with pandemic policies, and these governments demonstrated more effective deployment of healthcare resources. The authors reject alternative explanations offered in prior studies, demonstrating that leader gender remains a significant predictor even after controlling for confounding factors. The findings contribute to the literature on gender and political leadership, emphasizing that the impact of descriptive representation extends beyond symbolic value and has real implications for policy outcomes—particularly in times of national crisis.

This book chapter challenges the conventional way in which political scientists define the end of parliamentary governments. It critiques the dominant practice of classifying any intra-coalition party change as a government termination, arguing that this approach inflates the number of government changes and skews comparative analyses across countries. To address this, the authors introduce a more precise definition that considers a government terminated only under three conditions: the installation of a new prime minister, the occurrence of a general election, or a partisan realignment that results in the loss of a governing majority. Using data from 28 OECD democracies, they show that this refined approach reveals that existing metrics often exaggerate government instability, leading to misinterpretations of institutional effectiveness.

Fernandes Jorge, Yael Shomer and Matthew Shugart. 2024. “Electoral Systems and the Personal Vote”, in Adrian Vatter and Rahel Freiburghaus (Eds.) The Handbook of Comparative Political Institutions, Edward Elgar Publishing.

This review article revisits and synthesizes nearly three decades of research sparked by Carey and Shugart’s (1995) seminal work on the personal vote—defined as the portion of a candidate’s electoral support rooted in personal traits, actions, and reputation rather than party affiliation. The authors examine how electoral systems incentivize personal vote-seeking and present a comprehensive overview of how the concept has been theorized, measured, and empirically studied across different contexts. They introduce a two-dimensional framework based on delegation theory and legislators’ goals to organize the literature, clarifying distinctions between systems that prioritize party-centered versus candidate-centered representation. The article critically assesses the methodological tools used to measure personal vote incentives and identifies several limitations in the existing literature, such as inconsistent metrics and underdeveloped connections to broader theories of democratic representation. It also highlights how personal vote-seeking behavior intersects with pressing normative questions, including responsiveness to constituents and the inclusion of historically marginalized groups. The authors conclude by outlining a forward-looking research agenda, calling for more rigorous conceptualization, cross-national data, and exploration of how personal vote incentives influence legislative behavior and democratic legitimacy in evolving electoral environments.  

Yael Shomer and Gert-Jan, Put. 2023 “Are citizens more politically engaged when candidate selection is democratic? Analysis of seven parliamentary election cycles in Israel (1996-2015)”, Political Research Quarterly, 76(3), pp.1119-1133 [IF 3.254; 67/187, Q2].

This study examines whether democratic candidate selection processes—such as primaries and other inclusive nomination methods—encourage higher levels of political engagement among citizens. Drawing on public opinion data from seven Israeli election cycles (1996–2015) and original data on party candidate selection processes, the authors assess how intra-party democratization shapes both electoral and partisan participation, as well as broader forms of political engagement like following campaign news and discussing politics. Contrary to widespread assumptions, the findings reveal that while democratic selection processes are associated with increased political engagement, they do not significantly affect actual voter turnout or participation in party activities. The study suggests that democratizing internal party procedures may enhance citizens’ attentiveness to politics and foster greater political interest, but these reforms alone do not necessarily translate into concrete political behavior. This structural disconnect between engagement and participation highlights the limits of procedural reforms in generating deeper civic involvement. The research contributes to the literature on intra-party democracy by emphasizing the importance of distinguishing between different forms of political involvement and by grounding the analysis in longitudinal data from a dynamic multiparty parliamentary system. 
  

Yael Shomer, Bjørn Erik Rasch and Osnat Akirav. 2022. “Termination of parliamentary governments: revised definitions and implications”, West European Politics, 45(3), pp. 550-575. [IF 4.055; 30/187 Q1, 13 citations].

This article reconsiders how political scientists define the termination of parliamentary governments, challenging the widespread approach that treats any intra-coalition partisan change as a government termination. The authors argue that this standard definition artificially inflates the number of governments, distorting cross-national comparisons and theoretical conclusions about government duration and stability. They propose a revised conceptualization that counts only three types of events as government terminations: the appointment of a new prime minister, a general election, or a partisan shift that causes the loss of majority status. Applying this refined framework to data from 28 OECD democracies, they demonstrate that traditional metrics overestimate government instability in certain countries, leading to biased assessments of institutional performance. The article makes both theoretical and empirical contributions. It shows that adopting the revised definition alters key conclusions about government duration. By advocating for a more consistent and substantively meaningful classification of government change, the authors provide scholars with a stronger foundation for comparative research on coalition politics, executive-legislative relations, and democratic stability. Their findings urge a reconsideration of standard datasets and encourage the adoption of measurement practices that better reflect the political realities of parliamentary systems.   

Shomer, Yael. 2020. “Women’s Representation in Israel: Between Selection Processes and Protective Mechanisms”. In Gender Gaps in Israeli Politics, ed. Michal Shamir, Hanna Herzog and Naomi Chazan, Van Leer Institute Press.

Scholars disagree about the way candidate selection processes affect women’s representation. While some argue that primaries benefit women candidates, other claim the opposite. I test the effect of selection procedures on female representation and find primaries to benefit it. I caution, however, against concluding that democratic selections are beneficial. I argue that party leaders are aware of primaries’ negative effects and they offset them by adopting partisan protective mechanisms. Therefore, controlling for partisan protective mechanisms will unveil the negative effect of primaries on female representation. Using party level data from eight legislative terms of the Israeli Knesset I find support for my hypotheses.   
  

Shomer Yael Gert-Jan Put, and Einat Gedalya-Lavy. 2018. Does intraparty democracy affect levels of trust in parties? The cases of Belgium and Israel, Acta Politca 53, pp. 167-183 [IF: 1.269; 55/161, Q2, 18 citations].

This article examines whether and how intra-party democracy—specifically, the mechanisms used for candidate selection—influences public trust in political parties. Focusing on Belgium and Israel, two multiparty parliamentary systems where intra-party democratization has been prominently debated, the study combines comparative public opinion data and party-level selection mechanisms. The authors find that inclusive candidate selection processes, which expand participation to broader selectorates, tend to increase trust in parties. In contrast, decentralized selection processes, which transfer authority to sub-national levels or local branches, are associated with lower levels of party trust.   By disentangling different dimensions of candidate selection (inclusiveness and centralization), the paper contributes to the literature on political trust and party organization. It underscores the importance of how parties structure their internal decision-making processes and suggests that reforms aimed at enhancing intra-party democracy can improve public perceptions, but only under specific organizational conditions. This research has implications for both party strategy and broader democratic legitimacy in representative systems.   

Shomer, Yael. 2017. "Institutional reforms and their effect on legislators’ behavior: The Israeli experience, 1992–2011", Party Politics 23(3), pp. 297-308 [IF 2.286; 19/161, Q1, 5 citations].

This study investigates how electoral and institutional reforms shape the behavior of legislators in parliamentary systems, using Israel as a case study. Focusing on a series of key institutional changes—including the adoption and later repeal of the direct election law for the prime minister—the paper examines how these reforms influenced legislative activism, party loyalty, and coalition dynamics. Drawing on an original dataset covering all Israeli legislators from 1992 to 2011, the study reveals that reforms intended to strengthen executive authority and voter-party linkages had unintended consequences, including increased legislative fragmentation and reduced party discipline. By analyzing variation in parliamentary behavior over nearly two decades of reform, the article contributes to the broader literature on institutional design and political behavior and accountability. It demonstrates that changes in electoral rules can recalibrate the incentives facing individual legislators, shifting their strategic behavior in ways that may undermine rather than enhance governability. The Israeli case highlights the complexity of institutional engineering in multiparty democracies and underscores the need for careful empirical evaluation of reform outcomes before drawing normative conclusions about their effectiveness.   
  

Shomer, Yael. 2016. “The Electoral Environment and Legislator Dissent”, Comparative Politics, 48(4), pp.557-578. [IF 1.417; 49/161, Q2, 16 citations]

I assert that since electoral systems and selection processes are substitutive means for ensuring a parties’ unified voting record the magnitude of the effect of candidate selection processes on legislators’ behavior will depend on the degree to which voters are allowed to disturb the party’s ballot at the general election stage. Since candidate selection procedures may vary within an electoral system, legislators might face contradictory incentives. While the electoral rules may encourage legislators to personalize, selections may incentivize them to behave in a party-centered way. Alternatively, while electoral systems incentivize party centeredness, selection procedures may encourage representatives to emphasize personal reputation. Given the possibility for contradictory incentives, I hypothesize and empirically examine how these contradictory incentives would affect legislators’ tendencies to dissent. I originally argue that the effect of elections and selections on legislators’ tendency to dissent is conditional, and that legislators who face contradictory incentives will tend to maintain voting discipline. On the other hand, when the incentives of elections and selections align, they tend to amplify one another. This is especially true when elections and selections both incentivize personalization. In this paper, I measure legislators’ behavior as the percentage of times a legislator voted against his party majority and I test and find support for the conditional hypothesis using an original individual-level dataset with 6,776 legislators from 180 parties in 30 country-sessions. This paper adds to our theoretical and empirical understanding of legislators’ behavior in multiple ways: to begin with, it challenges the amalgamation between elections and selections, which is prevalent in the current literature, and hypothesizes about their combined conditional effect. As such, the paper studies the way political institutions interact in influencing elites’ behavior, and more realistically depict the possibility that legislators are facing conflicting incentives produced by differing and separate political institutions. Second, while most research to date used a party-level measure of behavior, (e.g., Rice or weighted Rice scores ), and those few that used individual level measurement confined the scope of research to one or only a few countries, in this paper I present an individual level, cross-national analysis of institutional effects on legislators’ behavior. To this end, I collected an original dataset containing individual level voting data for more than 6,700 legislators from 30 country sessions.   

Shomer Yael, Gert-Jan Put and Gedalya-Lavy Einat. 2016. "Intra-Party Politics and Public Opinion: How Candidate Selection Processes Affect Citizens’ Satisfaction with Democracy", Political Behavior, 38(3), pp. 557-578. [IF 2.868; 9/161, Q1, 46 citations].

This article investigates how the internal democratic practices of political parties—specifically, the procedures used for selecting candidates—affect citizens’ satisfaction with democracy. While political parties are widely acknowledged as critical institutions in representative democracies, their influence on public opinion is often understudied. Drawing on a unique cross-national dataset covering 130 parties across 28 democracies, as well as in-depth analyses of Belgium and Israel, the authors assess whether voters who support parties with more democratic candidate selection processes report higher satisfaction with how democracy functions in their country.   The study finds a consistent relationship: democratic candidate selection processes are positively associated with citizens’ satisfaction with democracy. This association holds in both the cross-national analysis and in the case studies of Israel and Belgium, where selection mechanisms vary significantly. The findings suggest that intra-party democracy enhances democratic legitimacy from the ground up by shaping how citizens perceive the broader political system. This research contributes to the literature on political representation and democratic attitudes by highlighting the role of meso-level institutions—political parties—in mediating public trust and democratic satisfaction. 
  

Rosas, Guillermo, Shomer, Yael and Haptonstahl, Steve. 2015. “No News is News: Non-Ignorable Non-Response in Roll-Call Data Analysis”, American Journal of Political Science 59(2), pp. 511-528. [IF 4.506; 3/161, Q1 73 citations].

Roll-call votes are widely employed to infer the ideological proclivities of legislators. However, many roll-call matrices are characterized by high levels of nonresponse. Under many theoretical circumstances and political contexts, nonresponse cannot be assumed to be ignorable. Put it differently legislators “register” non-response (either by actively abstaining or by actively absenting themselves from the vote) strategically. In this innovative paper we examine the consequences of violating the ignorability assumption that underlies current prevalent methods of roll-call analysis. We first motivate our analysis by documenting the prevalence of item nonresponse in legislatures around the world. Second, we originally try to understand and document the severity of assuming strategic roll-call non-responses are ignorable. We then present a basic estimation framework to model nonresponse and vote choice concurrently and we build a model that captures the logic of competing principals that underlies accounts of nonresponse in many legislatures. We show that IRT models that assume random ignorable missingness generate biased inferences about ideal points compared to a model that incorporates assumptions from the competing principals logic. The MCMC simulations further show that this bias increases substantially with the rate of nonresponse. Lastly, we revisit two debates in international relations and American politics concerning abstentions in the United Nations General Assembly during the height of the Cold War, and the question of the “most liberal senator” that has come up in recent U.S. presidential elections. Indeed we show that modeling the process that ostensibly drives abstentions allows us to recover more consensual estimates of the distances that existed between the Soviet Union and some of its satellites and dispels the image of presidential hopefuls in the United States as ideological extremists. The simulations as well as real world data show that modeling presumed patterns of nonignorable nonresponse can yield important inferential payoffs over current models that assume random missingness. We, therefore, encourage scholars to think actively and carefully about potential processes that might generate strategic absences and abstentions in the legislatures they study. Before reaching conclusions about the ideological profiles of legislators, it is important to gauge the sensitivity of different legislator’s ideal points to nonignorable abstention-generating mechanisms deemed relevant in the legislature at hand. 
  

Shomer, Yael. 2015. "Electoral Incentives and Individual Parliament Members’ Rights", West European Politics, 38(5), pp. 1106-1127. [IF 1.692; 38/161, Q1, 5 citations].

Cameral procedures define the modus operandi of a parliament. While the vast majority of the literature study the effect cameral procedures have on executive-legislative relationships, I originally focus scholarly attention on an additional dimension which is directly affected by legislative procedures: the individual MP vis-à-vis the leadership dimension. I, thus, broaden the scope of institutional structures that affect legislative behavior, by focusing attention on an often neglected institution in the comparative literature: intra-cameral procedures. In addition to arguing that legislative procedures affect politicians’ rights and the balance of power between the individual MP vis-à-vis the leadership, I also claim that cameral procedures are not a static institution. Therefore, I innovatively, present a theory of cameral procedure amendments that result from the external electoral-selectoral environment. I argue that governments’ incentives to restrict Parliament Members’ (MPs‘) rights are affected by MPs‘ (s)electoral motivation to emphasize individualistic behavior at the expense of their party’s reputation, hence overusing (arguably abusing) their individual rights. Governments and the Heads of the Executive in particular will react to these electoral incentives by restricting and limiting MPs’ rights in the cameral procedures. In the article I specifically hypothesize that when the electoral environment motivates legislators to act individualistically governments are incentivised to restrict cameral procedures to curtail legislators’ behaviour. I further contend that materialising such incentives depends on the government’s ability to pass restrictive procedural changes. To test the theory, four decades (1967–2007) of amendments to the Israeli Knesset’s rules of procedure were examined and support provided for co-variation of changes to the (s)electoral environment (emphasizing individualistic behavior) and restrictiveness of the Knesset’s procedures. The analysis then details the factors that enabled Israeli governments to pass such restrictive measures. The analysis reveals that governments in Israel seem to use the rules of procedure strategically in their attempt to improve their control and curtail legislators’ behaviour. As such, legislative rules are tools used by political leaders and the executive to attenuate hypothesized personalized incentives produced by external institutions such as electoral systems and candidate selection processes.   
  

Shomer, Yael. 2014. "What Affect Candidate Selection Processes? A Cross-National Examination", Party Politics, 20(4), pp. 533-546. [IF 2.286; 19/161, Q1, 127 citations].

This article seeks to examine empirically what factors account for variation in candidate selection processes. After identifying the key assertions developed in the literature, I use an original cross-national dataset with data on the selection procedures of 512 parties in 46 countries (the largest comparative dataset to the best of my knowledge) to examine whether a party’s ideology, size, regime type, territorial organization and region affect the way parties select their legislative candidates. In the article I pay special and close attention to the hypothesized relationships between electoral systems and selection processes. This is because most of the literature on the effects of institutions on legislators’ behavior often amalgamated elections and selections. I argued that underlying this amalgamation is an assumption that electoral systems determine candidate selection processes. Only to the degree to which electoral systems determine parties’ selection processes can scholars amalgamate elections and selections into a single (and the same) institution, and study its effect on behavior. The results from the analysis empirically challenge the literature’s amalgamation. The article’s contribution to the study of candidate selection processes and legislators behavior is twofold. On the one hand, this is the largest cross-national analysis (to the best of my knowledge) of candidate selection processes’ determinants, in which the appropriate unity of analysis is used: a party prior to a given election. On the other hand, the results from the paper laid the ground for the my argument that literature should differentiate elections from selections and allow for the theoretical and empirical possibility that elections and selection might produce combined conflicting incentives for parties’ and legislators’ behavior. 
  

Shomer, Yael and O’Brien, Diana. 2013. “A Cross-National Analysis of Party Switching”, Legislative Studies Quarterly, 38(1), pp. 111-141.[IF 1.239; 50/143, Q2, 154 citations]

Though interparty movement has been documented in legislatures across a number of countries, and although party switching can significantly influence democratic representation and governance, there has been comparatively little systematic cross-national research on party switching. Thus, the prevalence of switching is unknown and the extent to which party- and system-level variation influences this behavior remains unclear. To address this lacuna, we have conducted the most comprehensive study of intra session party switching that has ever been undertaken. Using our original dataset, we begin by examining the prevalence of party switching across 239 party-level observations in 20 democratic regimes. To theoretically explain variation in the presence and prevalence of party switching both across and within legislatures, we draw on the theoretical literature on intraparty switching and legislators’ behavior. We specifically look at the relationship between legislators’ motivations, institutional determinants and party switching. This article makes two major contributions to the study of interparty movement. First, using the largest and most comprehensive cross-national dataset on party-level switching ever constructed, we illustrate that contrary to popularly held assumptions, party switching occurs much more frequently than previously asserted. Of the 239 parties included in the dataset, almost one-third (78) exhibited some switching. This is an important finding in and of itself, as it demonstrates that defection is not a rare phenomenon, but instead a serious issue facing parties in democratic states. This in turn calls for scholars of legislative politics to dedicate greater attention to the study of interparty movement. In addition to showing the prevalence of party switching, we offer new insights into the determinants of this behavior. The results from our varying-intercept random effects models demonstrate that motivational factors influence interparty movement, while the direct effect of institutional arrangements is minimal. We suggest that future research will have to amend our treatment of the motivational and institutional treatments as two distinct theoretical approaches and treat motivations and institutions as endogenous to one another. 
  

Shomer, Yael. 2009. “Candidate Selection Procedures, Seniority, and Vote-Seeking Behavior: Lessons from the Israeli Experience.” Comparative Political Studies, 42(7), pp. 945-970. [IF 1.908; 16/91, Q1, 129 citations]

It has been argued that inclusive and decentralized selection procedures create greater incentives for parliamentarians to enhance their personal reputations. However, while the observable implications of this theory are at the level of individual members, the empirical data often brought to bear on this question to date have been collected at an aggregate level-– the partisan bloc or legislative term. Despite some previously positive aggregate results I find no discernible support for the connection between candidate-selection procedures and vote-seeking behavior in Israel at the individual parliamentarian level. I suggest an alternative theory—based on the stage of the legislative career—that explains both individual-level behavior and the aggregate-level trend.   Rosas, Guillermo and Yael Shomer. 2009. “Non-ingnorable Abstentions in Mexico’s Instituto Federal Electoral". In The Political Economy of Democracy, ed. Enriqueta Aragonès, Carmen Beviá, Humberto Llavador and Norman Schofield, pp. 245-261.   The purpose of this paper is to explore empirically some of the effects of assuming different abstention-generating mechanisms on the estimation of ideal points. For this purpose, we inspect a small committee, the Council-General of the Mexican Federal Electoral Institute (IFE, by its Spanish acronym). Though we start from common wisdom propositions about the putative ideological profiles of IFE Councilors, we do not purport to provide a theoretically-nuanced approximation to the ideological organization of this Council. Instead, we use the Council’s roll-call record to gauge how inferences about ideology would be affected by different assumptions about Councilors’ motivations to abstain. In this regard, our approach to the politics of IFE is unabashedly empirical, and indeed the choice of this committee as an object of study is driven by various characteristics that we deem desirable in this kind of exploratory analysis: IFE’s Council-General is a committee made up of a handful of with known political sponsors, it decides on extremely important electoral matters, and it produces a relatively high incidence of abstentions.

Rosas, Guillermo and Yael Shomer. 2008. “Models of Nonresponse in Legislative Politics.” Legislative Studies Quarterly 33(4), pp. 573-601. [1.061; 35/89, Q2, 68 citations].

Tools dedicated to inferring the ideological leanings of legislators from observed votes–techniques such as Nominate (Poole and Rosenthal 1997) or the item-response theory model of Clinton, Jackman and Rivers (2004)–are based on the assumption that the political process that generates abstentions is ignorable, an assumption that is not always easy to justify. We extend the item-response theory model to analyze abstention and voting processes simultaneously in situations where abstentions are suspected to be non-random. We apply this expanded model to two assemblies where the existing literature gives us reasons to expect non-random abstentions, and suggest how our extensions yield nuanced analyses of legislative politics. We also acknowledge limits to our ability to decide on the adequacy of alternative assumptions about abstentions, since these are not readily verifiable. 
  

Crisp, Brian F., Kathryn M. Jensen, and Yael Shomer. 2007. “Magnitude and Vote Seeking.” Electoral Studies 26(4), pp. 727-734. [IF 1.067; 23/84, Q2, 130 citations].

In one of the most frequently cited articles published in Electoral Studies, Carey and Shugart [Cary, J.M.Shugart, M.S. 1995. Incentives to cultivate a personal vote: a rank ordering of electoral formulas. Electoral Studies 14(4), 417-439] hypothesized that the number of copartisans faced relative to seats available had a differential effect on the incentive to cultivate a personal vote depending on whether electoral rules allowed for intra-party competition. Across a wide array of electoral systems, we show that the number of candidates fielded per party varies within districts and that the variation is not systematically related to the total number of seats available. Thus, the widespread use of magnitude as a proxy for ‘‘copartisan crowdedness’’ is systematically inaccurate.We argue that the observed number of copartisans faced makes clear that a ratio to capture vote seeking incentives needs a party-in-adistrict denominator to accompany the party-in-a-district numerator. That denominator is the expected number of seats to be won by each party in question.