About

The provided page text does not contain a professional biography or detailed background information about Professor Jeffrey B. Lewis. Therefore, the JSON output is an empty string for the biography.

Research topics

• Political Science
• Computer Science
• Political economy
• Social Science
• Computer Security
• Economics
• Sociology
• Law
• Internet privacy
• Psychology
• Business
• Social psychology
• History
• Positive economics

Selected publications

• Accounting for Protest Voting in the U.S. Congress

  Political Analysis · 2026-02-25

  articleOpen accessSenior author

  Abstract Members of the majority party in Congress sometimes vote against bills that they prefer over the status quo. We estimate a model of congressional roll-call voting that allows for this kind of non-ideological protest voting. We find that protest voting has significant implications for roll-call-based estimates of ideology and other analyses that rely upon them. For example, a traditional item response theory model curiously identifies members of the Squad as relatively moderate Democrats, but our protest-voting-adjusted scores identify them as the most liberal members of Congress. We also find that previous studies may have underestimated responsiveness, the effects of ideology in elections, the utility of non-roll-call-based measures of ideology, and the increase in congressional polarization. Although the implications for most substantive applications are likely modest, our analyses suggest that future researchers can better measure legislative ideology by accounting for a small number of non-ideological votes.

  PublisherOA PDFDOI

• Replication Data for: Accounting for Protest Voting in the U.S. Congress

  Open MIND · 2025-12-02 · 1 citations

  datasetSenior author

  Members of the majority party in Congress sometimes vote against bills that they prefer over the status quo. We estimate a model of congressional roll-call voting that allows for this kind of non-ideological, protest voting. We find that protest voting has significant implications for roll-call-based estimates of ideology and other analyses that rely upon them. For example, a traditional IRT model curiously identifies members of the Squad as relatively moderate Democrats, but our protest-voting-adjusted scores identify them as the most liberal members of Congress. We also find that previous studies may have underestimated responsiveness, the effects of ideology in elections, the utility of non-roll-call-based measures of ideology, and the increase in congressional polarization. Although the implications for most substantive applications are likely modest, our analyses suggest that future researchers can better measure legislative ideology by accounting for a small number of non-ideological votes.

  DOI

• Privacy violations in election results

  Science Advances · 2025-03-12

  articleOpen access

  After an election, should election officials release a copy of each anonymous ballot? Some policy-makers have championed public disclosure to counter distrust, but others worry that it might undermine ballot secrecy. We introduce the term vote revelation to refer to the linkage of a vote on an anonymous ballot to the voter's name in the public voter file and detail how such revelation could theoretically occur. Using the 2020 election in Maricopa County, Arizona, as a case study, we show that the release of individual ballot records would lead to no revelation of any vote choice for 99.83% of voters as compared to 99.95% under Maricopa's current practice of reporting aggregate results by precinct and method of voting. Further, revelation is overwhelmingly concentrated among the few voters who cast provisional ballots or federal-only ballots. We discuss the potential benefits of transparency, compare remedies to reduce or eliminate privacy violations, and highlight the privacy-transparency trade-off inherent in all election reporting.

  PublisherDOI

• How Partisan are U.S. Local Elections? Evidence from 2020 Cast Vote Records

  2025-05-12

  preprintOpen access

  Analyzing nominally partisan contests, previous literature has argued that state and local politics have nationalized. Here we use individual ballots from the 2020 general elections covering over 50 million voters to study the relationship between individual national partisanship and voting in over 5,700 contested down-ballot contests, including nonpartisan races and ballot measures. Voting in partisan contests can be explained by voter’s national partisanship, consistent with existing literature. However, we find that voting for local nonpartisan offices and ballot measures is much less partisan. National partisanship explains more than 80 percent of the within-contest variation in voting for partisan state and local offices but less than 10 percent for local nonpartisan contests and local ballot measures. The degree of partisanship in local spending measures varies by the type of service – e.g., education, roads, public safety, housing. Finally, we find evidence of structure in the pattern of votes on local spending measures.

  PublisherOA PDFDOI

• Privacy Violations in Election Results

  SSRN Electronic Journal · 2025-01-01

  articleOpen access
  PublisherDOI

• Cast vote records: A database of ballots from the 2020 U.S. Election

  SSRN Electronic Journal · 2025-01-01

  preprintOpen access
  PublisherDOI

• How Partisan Are U.S. Local Elections? Evidence from 2020 Cast Vote Records

  American Political Science Review · 2025-09-26

  articleOpen accessCorresponding

  Analyzing nominally partisan contests, previous literature has argued that state and local politics have nationalized. Here we use individual ballots from the 2020 general elections covering over 50 million voters to study the relationship between individual national partisanship and voting in over 5,700 contested down-ballot contests, including nonpartisan races and ballot measures. Voting in partisan contests can be explained by voter’s national partisanship, consistent with existing literature. However, we find that voting for local nonpartisan offices and ballot measures is much less partisan. National partisanship explains more than 80% of the within-contest variation in voting for partisan state and local offices but less than 10% for local nonpartisan contests and local ballot measures. The degree of partisanship in local spending measures varies by the type of service—for example, education, roads, public safety, housing. Finally, we find evidence of structure in the pattern of votes on local spending measures.

  PublisherDOI

• Cast vote records: A database of ballots from the 2020 U.S. Election

  Scientific Data · 2024-11-28 · 7 citations

  articleOpen access

  Ballots are the core records of elections. Electronic records of actual ballots cast (cast vote records) are available to the public in some jurisdictions. However, they have been released in a variety of formats and have not been independently evaluated. Here we introduce a database of cast vote records from the 2020 U.S. general election. We downloaded publicly available unstandardized cast vote records, standardized them into a multi-state database, and extensively compared their totals to certified election results. Our release includes vote records for President, Governor, U.S. Senate and House, and state upper and lower chambers, covering 42.7 million voters in 20 states who voted for more than 2,200 candidates. This database serves as a uniquely granular administrative dataset for studying voting behavior and election administration. Using this data, we show that in battleground states, 1.9 percent of solid Republicans (as defined by their congressional and state legislative voting) in our database split their ticket for Joe Biden, while 1.2 percent of solid Democrats split their ticket for Donald Trump.

  PublisherOA PDFDOI

• How Partisan are U.S. Local Elections? Evidence from 2020 Cast Vote Records

  2024 · 3 citations

  • Political Science
  • Political Science
  • Political economy

  Analyzing nominally partisan contests, previous literature has argued that state and local politics have nationalized. Here we use individual ballots from the 2020 general elections covering over 43 million voters to study the relationship between individual national partisanship and voting in over 4500 down-ballot contests, including nonpartisan races and ballot measures. Voting in partisan contests can be explained by voter’s national partisanship, consistent with existing literature. However, we find that voting for local nonpartisan offices (n = 1484 contests) and ballot measures (n = 1576) is much less partisan. National partisanship explains more than 80 percent of the within-contest variation in voting for partisan state and local offices but less than 10 percent for local spending-related ballot measures. Voting for spending on roads and water are less partisan than those on education and housing, and these votes are more correlated with each other than with national partisanship.

  PublisherOA PDFDOI

• Cast vote records: A database of ballots from the 2020 U.S. Election

  arXiv (Cornell University) · 2024-10-24

  preprintOpen access

  Ballots are the core records of elections. Electronic records of actual ballots cast (cast vote records) are available to the public in some jurisdictions. However, they have been released in a variety of formats and have not been independently evaluated. Here we introduce a database of cast vote records from the 2020 U.S. general election. We downloaded publicly available unstandardized cast vote records, standardized them into a multi-state database, and extensively compared their totals to certified election results. Our release includes vote records for President, Governor, U.S. Senate and House, and state upper and lower chambers -- covering 42.7 million voters in 20 states who voted for more than 2,204 candidates. This database serves as a uniquely granular administrative dataset for studying voting behavior and election administration. Using this data, we show that in battleground states, 1.9 percent of solid Republicans (as defined by their congressional and state legislative voting) in our database split their ticket for Joe Biden, while 1.2 percent of solid Democrats split their ticket for Donald Trump.

  PublisherOA PDFDOI

Recent grants

• Collaborative Research on Dynamic Models of Roll Call Voting

  NSF · $182k · 2006–2011

Frequent coauthors

• Gary King

  Harvard University Press

  636 shared

• Kenneth Benoit

  629 shared

• Micah Altman

  Massachusetts Institute of Technology

  629 shared

• Greg Adams

  628 shared

• Russ Mayer

  628 shared

• Bradley Palmquist

  Syracuse University

  628 shared

• Claudine Gay

  628 shared

• Eric Reinhardt

  Emory University

  628 shared

Awards & honors

• President of the Society for Political Methodology