Welcome! I am an Assistant Professor of Political Science in the School of Public and International Affairs at the University of Cincinnati. I am also a Research Affiliate with the Portman Center for Policy Solutions.
I study American legislatures, with a particular focus on Congress, campaigns and elections, and identity. I specialize in quantitative methods and use big data, machine learning, and causal inference in my research. My work is published in outlets such as Political Research Quarterly, PS: Political Science & Politics, and State Politics & Policy Quarterly.
I received my Ph.D. in Political Science from the University of Virginia in 2025. Before UVA, I earned a B.A. in Politics and International Affairs, with a minor in Poverty Studies, from Furman University.
Publications
I’m Coming Out! How Voter Discrimination Produces Effective LGBTQ Lawmakers
Jacob M. Lollis and Mackenzie R. Dobson.
PS: Political Science & Politics, 2025.
PDF DOI Replication
Abstract
Are LGBTQ legislators effective lawmakers? We build on theories that link voter discrimination to legislative effectiveness by arguing that voters’ biases against LGBTQ candidates narrow the candidate pool, leading to the election of only the most experienced and qualified LGBTQ candidates. As a result of this electoral selection effect, we expect that LGBTQ legislators will be more effective lawmakers than their non-LGBTQ counterparts. To test this, we combine data on state legislators’ LGBTQ identification with their State Legislative Effectiveness Scores (SLES). Our findings reveal that LGBTQ legislators are meaningfully more effective than non-LGBTQ legislators. To link our findings to voter discrimination, we leverage over-time variation in discrimination toward LGBTQ individuals. Across four tests, we consistently find that LGBTQ lawmakers elected in highdiscrimination environments are more effective than those elected from less discriminatory environments.
Race, Contact Effects, and Effective Lawmaking in Congressional Committee Hearings
Jacob M. Lollis
Political Research Quarterly, 2025.
PDF DOI
Abstract
Though there is strong evidence that nonwhite lawmakers introduce more racially salient legislation than white lawmakers, it is less clear whether race is a significant predictor of other legislative behavior. Given mixed findings in existing research, lawmakers’ actions in committee offer a new test of how race shapes legislative behavior. I develop new, original measures identifying race references in more than 1.4 million congressional committee hearing statements. I find that nonwhite lawmakers discuss race more frequently than white lawmakers in hearings, though white lawmakers are more likely to mention race in racially diverse hearings due to contact effects. Using a novel measure of race-issue bills, I demonstrate that lawmakers’ race statements in hearings are linked to policy representation. These findings explain how racial diversity in legislatures affects legislative speech and policy representation.
Are Workers Effective Lawmakers?
Jacob M. Lollis
State Politics & Policy Quarterly, 2024.
PDF DOI Replication
Abstract
Are workers effective lawmakers? Throughout American history, some politicians and elites have argued that white-collar Americans are more qualified than working-class Americans to govern. To date, however, we know relatively little about the legislative effectiveness of working-class lawmakers. I develop a theory of class-based electoral selection that links class-based discrimination in elections to legislators’ performance in office. I argue that working-class candidates face class-based biases in elections that make it more difficult to emerge and successfully win elective office. As a result, I expect the working-class candidates who do become lawmakers to be equally or more effective than their white-collar colleagues. To test these expectations, I create a data set merging the occupational background of more than 14,000 individual state legislators with their state legislative effectiveness score (SLES). The resulting data set includes more than 50,000 state legislator-term specific observations. Consistent with my expectations, I find that working-class lawmakers do not underperform white-collar lawmakers. Further, I provide evidence that, across various models and specifications, the gap between working-class and white-collar legislators’ effectiveness is negligible.
Nothing to See Here: Republican Congressional Members’ Twitter Reactions to Donald Trump,
C. Danielle Vinson and Jacob M. Lollis
Congress & The Presidency, 2023.
DOI Replication
Abstract
How do co-partisans respond to the President on Twitter? This article examines whether and how Republican legislators reacted to President Trump in five instances when he broke with Republican Party policy positions or norms. We theorize that legislators’ electoral environment, constituency, and identity shape their response to the president, and we test our hypotheses using nearly 2,500 hand-coded tweets from Republican legislators between 2018-2020. The overwhelming reaction by Republican legislators to Trump’s actions was to ignore him. When members did react to the president, their response was primarily driven by their electoral environment and identity. Those from the most Trump supportive districts supported the president, and retiring members were most likely to oppose him. Male legislators were much more likely to support and oppose the president, while female legislators mostly ignored him. And, if they reacted, the most ideologically extreme Republicans were more likely to support than oppose the president. The implications of these findings are troubling. Even when President Trump violated traditional norms or deviated from long held party positions, his congressional co-partisans remained silent, occasionally offering support but rarely opposition.
Working Papers
Learning in Committee? How Racial Diversity Shapes Speech, Evidence Use, and Substantive Representation in Congress
Jacob M. Lollis
Status: Revise and Resubmit
Last Update: April 2026
Paper
Abstract
Although increased racial diversity in American legislatures has expanded attention to race, particularly among nonwhite lawmakers, we know much less about how committee racial diversity shapes interactions between nonwhite and white legislators. I argue that repeated contact with nonwhite lawmakers in racially diverse committees may shape how white Democrats engage race-related issues, making them more likely to support race-related hearing statements with evidence. To test this expectation, I combine large-scale text classification with a detailed content analysis of more than 11,000 race-based committee hearing statements and 87,000 full bill texts from the 105th–117th Congresses. Using a within-legislator design, I find that white Democrats serving on racially diverse committees are more likely to reference evidence when discussing race and to cite the same sources as their nonwhite colleagues. I then show that this relationship is consistent with white Democrats learning from nonwhite lawmakers’ use of evidence, though I am unable to fully rule out all alternative explanations. Finally, I demonstrate that race-based expertise is associated with substantive representation, as legislators who more frequently cite evidence when discussing race are more effective at advancing race-related legislation. Together, these findings suggest that descriptive representation may foster substantive representation, in part, by shaping how white Democrats engage race-related issues in racially diverse legislative committees.
Legislative Professionalism and Perceptions of White-Collar Government
Mackenzie R. Dobson, Jacob M. Lollis, Jeffrey J. Harden, and Justin H. Kirkland
Status: Revise and Resubmit
Last Update: February 2026
Abstract
The professionalization of American state legislatures is among the most consequential modern institutional reforms in legislative politics. Yet a core tension persists: citizens disapprove of professionalized legislatures even though these chambers possess capacity-enhancing resources—such as staff support, higher salaries, and longer sessions—that may improve representation and policymaking. We offer one explanation for this disapproval: citizens perceive professional legislatures as dominated by legislators from white-collar backgrounds. Consequently, we argue that opposition to professionalism stems, in part, from a belief that white-collar legislators may not represent society’s interests broadly. Evidence from a preregistered conjoint experiment and observational analyses using the Cooperative Election Study (CES) supports this claim. Respondents associate professionalism with a legislature primarily composed of white-collar lawmakers, whom they do not believe govern to benefit the general public. These findings suggest that opposition to legislative professionalism likely reflects a rejection of white-collar government rather than repudiation of the institutional gains from professionalization.
Congressional Attention to Abortion after Dobbs: How
Representational and Electoral Incentives Selectively
Shape Issue Attention
Jacob M. Lollis and Mackenzie R. Dobson
Status: Under Review
Last Update: April 2026
Paper
Abstract
Landmark Supreme Court rulings can reshape policy, rights, and public opinion, but their effects on congressional issue attention remain less clear. We argue that such rulings do not uniformly reshape congressional attention; instead, they do so selectively, de- pending on how legislators’ representational and electoral incentives align. We test this argument in the case of Dobbs v. Jackson Women’s Health Organization (2022). We argue that, after Dobbs, abortion attention increased only when gender-linked representational consid- erations and party-based electoral incentives converged. These incentives aligned for female Democrats, but female Republicans faced electoral risks in foregrounding abortion, while male legislators faced weaker gender-linked representational incentives. Using nearly 1.6M statements from U.S. House committee hearings, we leverage the leak of the draft opinion in a difference-in-differences design that estimates differential changes in abortion attention across party and gender. Pre-treatment trends show no systematic differences. After the leak, female Democrats increased abortion-related references relative to female Republicans, with no change among male legislators.
The Concentration of Legislative Effectiveness:
Evidence from U.S. State Legislatures
Jacob M. Lollis and Todd Makse
Status: Under Reveiw
Last Updated: April 2026
Paper
Abstract
Research on legislative effectiveness has largely examined why some legislators are more successful than others. Yet legislatures also vary in how broadly policymaking success is shared across members. In this paper, we examine how institutional design shapes the distribution of policymaking power within legislatures. To do so, we develop the Effective Legislator Ratio (ELR), a chamber-level measure capturing the share of legislators who account for policy success. Using data from 94 U.S. state legislative chambers from 1997 to 2018, we show that policy success varies widely across chambers and is most concentrated for consequential legislation. Policymaking opportunity (i.e., chamber size and bill introduction limits) is more strongly associated with this distribution than agenda power (i.e., agenda control and leadership powers). Finally, when effectiveness is concentrated, new legislators adapt their cosponsorship strategies by learning which collaborators are most likely to advance legislation successfully.
Bipartisanship scores by member and issue area in the U.S. Congress, 1983–2024
Mackenzie R. Dobson and Jacob M. Lollis
Status: Pre-Review
Paper
Abstract
Although bipartisanship is central to legislative behavior and often necessary for policymaking success, no centralized, publicly accessible dataset tracks legislators' propensity to offer and attract cross-party support across time and policy issue areas. As a result, scholars are limited in answering key questions about whether bipartisanship is declining over time, who engages in it, which policy areas facilitate cross-party collaboration, and how such behavior shapes governing, representation, and democratic accountability. We introduce a dataset of congressional bipartisanship scores for all members of the U.S. House and Senate from 1983 to 2024. Built from more than 2.4 million cosponsorship decisions on 147,669 bills, the dataset provides two complementary member-term measures: attracting original out-party cosponsors to one's own bills and offering original cosponsorship to out-party-sponsored bills. The dataset includes aggregate and issue-specific scores across 34 policy issue areas for 2,056 unique legislators and 11,549 legislator-term observations. To facilitate broad reuse among academics, researchers, journalists, legislators, and the public, we make the dataset available through Harvard Dataverse and a corresponding R package, biparty.