Articles & Working Papers

Working Paper
Chilton, Adam, Daniel Epps, Kyle Rozema, and Maya Sen. Working Paper. “The Endgame of Court-Packing”. Publisher's Version Abstract
We estimate the size of the U.S. Supreme Court in a world in which the political parties engage in tit-for-tat court-packing. We do so by assuming that the Supreme Court is immediately expanded by four members and that future presidents who court-pack would add enough seats to ensure that a simple majority of justices were appointed by their party. In a series of simulations, we find that median result of repeated partisan court-packing would be to increase the size of the Court to 23 justices within 50 years and to 39 justices within 100 years. We also study the incentives for justices to retire strategically in a world with repeated partisan court-packing and the resulting effects of changes in strategic retirement on the size the Court. We find that court-packing would decrease the incentives for strategic retirement, but we also find that changes in justices’ retirement decisions would have little effect on the eventual size of the Court.
Bonica, Adam, Adam Chilton, and Maya Sen. Working Paper. “The “Odd Party Out” Theory of Certiorari”. Abstract
How justices advance their ideological preferences is among the most well-studied aspects of the Supreme Court. In contrast, we explore how justices may discourage ideologically motivated behavior: granting cert petitions when there is a high likelihood that ideological bias influenced the lower court. We theorize that cert is more likely when there is ideological distance between the parties and the lower court panel is ideologically distant to the losing side. In these cases, the party petitioning for cert becomes the "Odd Party Out,'" which conveys information about the possibility of lower court bias. We test the theory using a new dataset of nearly 18,000 cert petitions that incorporates advocate and judge ideology. We find strong support: Cert is more likely when the petitioner---regardless of their ideology---is the ideological Odd Party Out. This provides evidence that justices may set aside their ideological concerns and intervene against such behavior in the lower courts. 
What are the downstream political consequences of state activity explicitly targeting an ethnic minority group? This question is well studied in the comparative context, but less is known about the effects of explicitly racist state activity in liberal democracies such as the United States. We investigate this question by looking at an important event in American history—the internment of people of Japanese ancestry during World War II. We find that Japanese Americans who were interned or had family who were interned are significantly less politically engaged and that these patterns of disengagement increase with internment length. Using an identification strategy leveraging quasi-random camp assignment, we also find that camp experience matters: those who went to camps that witnessed intragroup violence or strikes experienced sharper declines, suggesting that group fragmentation is an important mechanism of disengagement. Taken together, our findings contribute to a growing literature documenting the demobilizing effects of ethnically targeted detention and expand our understanding of these forces within the U.S.
Baum, Matthew, Bryce Dietrich, Rebecca Goldstein, and Maya Sen. Working Paper. “Estimating the Effect of Asking About Citizenship on the U.S. Census: Results from a Randomized Controlled Trial”.
In Press
Chilton, Adam, Daniel Epps, Kyle Rozema, and Maya Sen. In Press. “Designing Supreme Court Term Limits.” Southern California Law Review. Abstract

Since the Founding, Supreme Court justices have enjoyed life tenure. This helps insulate the justices from political pressures, but it also results in unpredictable deaths and strategic retirements determining the timing of Court vacancies. In order to regularize the appointment process, a number of academics and policymakers have put forward detailed term limits proposals. However, many of these proposals have been silent on many key design decisions and there has been almost no empirical work assessing the impact that term limits would have on the composition of the Supreme Court.

This Article provides a framework for designing a complete term limits proposal and develops an empirical strategy to assess the effects of instituting term limits. The framework we introduce outlines the key design features that any term limits proposal must make, including frequently overlooked decisions like what the default would be if there is Senate inaction on a president’s nominee. The empirical strategy we develop uses simulations to assess how term limits proposals would have shaped the Court if they had been in place over the last 80 years of American history. These simulations enable comparative assessments of term limit proposals relative to each other and to the historical status quo of life tenure.

Using these simulations, we are able to isolate the design features of existing proposals that produce significant differences in the composition of the Supreme Court. For instance, proposals that commence appointing term-limited justices immediately could complete the transition in just 16 years, but proposals that wait until after the sitting justices leave the Court to appoint term limited justices would take an average of 52 years to complete the transition. Our results also reveal that term limits are likely to produce dramatic changes in the ideological composition of the Court. Most significantly, the Supreme Court had extreme ideological imbalance for 60 percent of the time since President Franklin Roosevelt’s effort to pack the Court, but any of the major term limit proposals would have reduced the amount of time with extreme imbalance by almost half.

Sen, Maya. 2021. “Written Testimony on the Importance of Judicial Diversity.” House Judiciary Subcommittee on Courts, Intellectual Property, and the Internet.
Harris, Allison P., and Maya Sen. 2019. “Bias and Judging.” Annual Review of Political Science 22: 241-259. Publisher's Version Abstract
How do we know whether judges of different backgrounds are "biased"? We review the substantial political science literature on judicial decision-making, paying close attention to how judges' demographics and ideology can influence or structure their decision-making. As the research shows, characteristics such as race, ethnicity, and gender can sometimes predict judicial decision-making in limited kinds of cases; however, the literature also suggests that these are by far less important in shaping or predicting outcomes than is ideology (or partisanship), which in turn correlates closely with gender, race, and ethnicity. This leads us to conclude that assuming judges of different backgrounds are biased because they rule differently is questionable: given that the application of the law rarely provides a ``correct'' answer, it is no surprise that judges' decisions vary according to their personal backgrounds and, more importantly, according to their ideology.
Kaufman, Aaron, Peter Kraft, and Maya Sen. 2019. “Improving Supreme Court Forecasting Using Boosted Decision Trees.” Political Analysis 27 (3): 381-387. Publisher's Version Abstract

Though used frequently in machine learning, boosted decision trees are largely unused in political science, despite many useful properties. We explain how to use one variant of boosted decision trees, AdaBoosted decision trees (ADTs), for social science predictions. We illustrate their use by examining a well-known political prediction problem, predicting U.S. Supreme Court rulings. We find that our ADT approach outperforms existing predictive models. We also provide two additional examples of the approach, one predicting the onset of civil wars and the other predicting county-level vote shares in U.S. presidential elections.

Bonica, Adam, Adam Chilton, Jacob Goldin, Kyle Rozema, and Maya Sen. 2019. “Legal Rasputins? Law Clerk Influence on Voting at the U.S. Supreme Court.” The Journal of Law, Economics, & Organization 35 (1): 1-36. Publisher's Version Abstract

Supreme Court justices employ law clerks to help them perform their duties. We study whether these clerks influence how justices vote in the cases they hear. We exploit the timing of the clerkship hiring process to link variation in clerk ideology to variation in judicial voting. To measure clerk ideology, we match clerks to the universe of disclosed political donations. We find that clerks exert modest influence on judicial voting overall, but substantial influence in cases that are high-profile, legally significant, or close decisions. We interpret these results to suggest that clerk influence occurs through persuasion rather than delegation of decision-making authority.

Dietrich, Bryce J., Ryan D. Enos, and Maya Sen. 2019. “Emotional Arousal Predicts Voting on the U.S. Supreme Court.” Political Analysis 27 (2): 237-243. Publisher's Version Abstract

Do Justices telegraph their preferences during oral arguments? We demonstrate that Justices implicitly reveal their leanings during oral arguments, even before arguments and deliberations have concluded. Specifically, we extract the emotional content of over 3,000 hours of audio recordings spanning 30 years of oral arguments before the Court. Using only the level of emotional arousal in each of the Justices’ voices during these arguments, as measured by their vocal pitch, we are able to accurately predict many of their eventual votes, while using none of the text or substantive content. These predictions are statistically and practically significant and robust to including a range of controls. Our findings suggest that mannerisms that may be subconscious, such as vocal pitch, carry information that basic legal, political, and textual information do not, and can be used to predict the decisions of even elite political actors.

scotus-audio.pdf scotus-audio-si.pdf
Bonica, Adam, Adam Chilton, Kyle Rozema, and Maya Sen. 2018. “The Legal Academy’s Ideological Uniformity.” Journal of Legal Studies 47 (1): 1-43. Publisher's Version Abstract
We study of the ideological balance of the legal academy and compare it to the ideology of the legal profession more broadly. To do so, we match professors listed in the Association of American Law Schools Directory of Law Teachers and lawyers listed in the Martindale-Hubbell directory to a measure of political ideology based on political donations. We find that 15 percent of law professors, compared to 35 percent of lawyers, are conservative. This may not simply be due to differences in their backgrounds: the legal academy is still 11 percentage points more liberal than the legal profession after controlling for several relevant individual characteristics. We argue that law professors’ ideological uniformity marginalizes them, but that it may not be possible to improve the ideological balance of the legal academy without sacrificing other values.
Acharya, Avidit, Matthew Blackwell, and Maya Sen. 2018. “Analyzing Causal Mechanisms in Survey Experiments.” Political Analysis 26 (4): 357-378. Publisher's Version Abstract

We present an approach to investigating causal mechanisms in survey experiments that leverages the provision or withholding of information on potentially important mediating variables. The designs we propose can identify the controlled direct effect of a treatment and also what we call an intervention effect. These quantities can be used to address substantive questions about causal mechanisms, can be identified under weaker assumptions than current approaches to causal mechanisms, and can be estimated with simple estimators using standard statistical software. Furthermore, these methods are compatible with a broad range of experimental designs, including survey vignettes and conjoint designs. We illustrate the approach via two examples, one on evaluations of potential U.S. Supreme Court nominees and the other on public perceptions of the democratic peace.

Acharya, Avidit, Matthew Blackwell, and Maya Sen. 2018. “Explaining Attitudes from Behavior: A Cognitive Dissonance Approach.” Journal of Politics 80 (2): 400-411. Publisher's Version Abstract

The standard approach in positive political theory posits that action choices are the consequences of preferences. Social psychology—in particular, cognitive dissonance theory—suggests the opposite: preferences may themselves be affected by action choices. We present a formal framework that applies this idea to three models of political choice: (1) one in which partisanship emerges naturally in a two party system despite policy being multi-dimensional, (2) one in which interactions with people who express different views can lead to empathetic changes in political positions, and (3) one in which ethnic or racial hostility increases after acts of violence. These examples demonstrate how incorporating the insights of social psychology can expand the scope of formalization in political science.

Hochschild, Jennifer, and Maya Sen. 2018. “Americans' Attitudes on Racial or Genetic Inheritance: Which is More Predictive?” Reconsidering Race: Social Science and Racial Categories in the Age of Genomics. Oxford University Press.
Ever since the Carter Administration began appointing female and minority judges in large numbers, scholars have sought to measure their impact. In this Article, I focus on a different, but equally important question: what is the background and ideology of female and minority judges and how has this changed over time? I address this issue empirically by analyzing quantitative data on United States district court judges from Presidents Lyndon Johnson through Barack Obama. My findings are twofold: First, I show that the professional and educational characteristics of female and minority judges have historically differed from those of white male judges, but these differences have narrowed over time, particularly when it comes to education. Second, I present evidence showing that, even though professional and educational differences have narrowed, female and minority judges still bring a different ideological viewpoint than do white male judges, being on average more left-leaning in their ideology. These findings reframe existing discussions about descriptive representation in the courts and suggest that female and minority judges more than ever tend to share professional and educational backgrounds with white or male judges, but still bring a different, albeit more liberal, perspective.
What predicts attempts at judicial reform? We develop a broad, generalizable framework that both explains and predicts attempts at judicial reform. Specifically, we explore the political tug of war created by the polarization between the bar and political actors, in tandem with existing judicial selection mechanisms. The more liberal the bar and the more conservative political actors, the greater the incentive political actors will have to introduce ideology into judicial selection. (And, vice versa, the more conservative the bar and the more liberal political actors, the greater incentive political actors will have to introduce ideology into judicial selection.) Understanding this dynamic, we argue, is key to both explaining and predicting attempts at judicial reform. For example, under most ideological configurations, conservatives will, depending on how liberal they perceive the bar to be, push reform efforts toward partisan elections and executive appointments, while liberals will work to maintain merit-oriented commissions. We explore the contours of this predictive framework with three in-depth, illustrative case studies: Florida in 2001, Kansas in the 2010s, and North Carolina in 2016.
Bonica, Adam, Adam Chilton, Jacob Goldin, Kyle Rozema, and Maya Sen. 2017. “Measuring Judicial Ideology Using Law Clerk Hiring.” American Law and Economics Review 19 (1): 129-161. Publisher's Version Abstract

We present a new measure of judicial ideology based on judicial hiring behavior. Specifically, we utilize the ideology of the law clerks hired by federal judges to estimate the ideology of the judges themselves. These Clerk-Based Ideology (CBI) scores complement existing measures of judicial ideology in several ways. First, CBI scores can be estimated for judges across the federal judicial hierarchy. Second, CBI scores can capture temporal changes in ideology. Third, CBI scores avoid case selection and strategic behavior concerns that plague existing vote-based measures. We illustrate the promise of CBI scores through a number of applications.

Bonica, Adam, Adam Chilton, Jacob Goldin, Kyle Rozema, and Maya Sen. 2017. “The Political Ideology of Law Clerks.” American Law and Economics Review 19 (1): 96-128. Publisher's Version Abstract

We study the political ideology of judicial law clerks in the United States, by constructing a novel dataset that combines information on the identity of clerks with a measure of political ideology based on political donations. We then use this data to empirically investigate several important questions about the ideologies of clerks. First, we examine whether clerks tend to share the liberal ideology of other lawyers or the more conservative ideology associated with federal judges and find that clerks tend to be disproportionately liberal. Second, we investigate how the ideology of clerks compares to the ideology of lawyers and find that liberal lawyers are more likely to have clerked than conservatives. Third, we assess whether the ideology of clerks differs based on the level of clerkship and find that the liberal skew becomes less pronounced as the prestige of the clerkship increases. Fourth, we analyze how ideology influences the hiring of clerks and find that the ideology of judges is strongly correlated with the ideology of their clerks.

Bonica, Adam, and Maya Sen. 2017. “A Common-Space Scaling of the American Judiciary and Legal Profession.” Political Analysis 25 (1): 114-121. Publisher's Version Abstract

We extend the scaling methodology previously used in Bonica (2014) to jointly scale the American federal judiciary and legal profession in a common-space with other political actors. The end result is the first data set of consistently measured ideological scores across all tiers of the federal judiciary and the legal profession, including 840 federal judges and 380,307 attorneys. To illustrate these measures, we present two examples involving the U.S. Supreme Court. These data open up significant areas of scholarly inquiry.


How do Americans evaluate potential U.S. Supreme Court candidates? Using a novel, two-part conjoint experiment, I show that respondents put high importance on the political leanings of potential Court candidates, a finding in contrast with the scholarly view that the public views the Court as different from other, more political institutions. Indeed, when respondents are given information about a nominee’s partisan leanings they rely extensively on that information in de- ciding whether to support the candidate, whether they trust the candidate, and whether they find the candidate qualified. By contrast, when partisan information is withheld, respondents appear to use other kinds of signals, such as race, in order to fill in the gaps. Those who are most knowledgeable about the Court are most influenced by these partisan signals, providing further support for the importance of political heuristics. The results suggest that the public’s evaluation of judicial nominees is more in line with how it evaluates other political actors. They also suggest that even candidates with excellent qualifications need not garner bipartisan public support.