Justin Grimmer

Senior Fellow

Justin Grimmer is a senior fellow at the Hoover Institution and a professor in the Department of Political Science at Stanford University. His current research focuses on American political institutions, elections, and developing new machine-learning methods for the study of politics.

His research examines how representation occurs in US politics using new statistical methods. His first book, Representational Style in Congress: What Legislators Say and Why It Matters (Cambridge University Press, 2013), shows how senators define the type of representation they provide constituents and how this affects constituents’ evaluations. The book was awarded the Fenno Prize in 2014 for best book published about Congress. His second book, The Impression of Influence: Legislator Communication, Representation, and Democratic Accountability (Princeton University Press, 2014, with Sean J. Westwood and Solomon Messing), demonstrates how legislators ensure they receive credit for government actions.

His current research projects include a book project on text as data methods for the social sciences, an examination of how electoral rules affect political participation, and an analysis of how social media affect democracies. His previous work has appeared in the American Political Science Review, American Journal of Political Science, Journal of Politics, Political Analysis, Proceedings of the National Academy of Sciences, Regulation and Governance, and several top computer science publication outlets.

He holds a PhD from Harvard University and an AB from Wabash College.

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Recent Commentary


In The Voter Fraud Debate, Be Wary Of Junk Science

by Justin Grimmer, Andrew B. Hall, Daniel M. Thompsonvia The Hill
Friday, August 27, 2021

Allegations of fraud in the 2020 U.S. election show no signs of slowing down. Former President Donald Trump continues to claim the 2020 election was stolen. The impact of those claims has caused significant harm to Americans’ faith in their elections; 71 percent identify illegally cast ballots as a problem in U.S. elections and 30 percent don’t believe Joe Biden was elected President. The summary dismissal of Trump’s charges by many in the establishment and mainstream media over the last 9 months has done nothing to reduce these numbers.

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Evaluating Look Ahead America’s ‘The Georgia Report’ On Illegal, Out-Of-State Voting In The 2020 Election

by Justin Grimmervia Analysis
Sunday, August 1, 2021

Given the critical importance of safeguarding the American electoral system, it is vital to evaluate the evidence offered for specific claims of fraud in the 2020 election. In this memo, we evaluate the methods used in Look Ahead America's April 19th, 2021 report, “The Georgia Report,” on illegal voting in Georgia in the 2020 election. The Georgia Report is among the most-cited pieces of evidence offered to support the claim that there was widespread fraud in the 2020 election. 


Dismantling Trump's Election Fraud Claims

by Justin Grimmer, Andrew B. Hallvia The Washington Times
Monday, February 8, 2021

People must look at the assertions being made, and the evidence and logic to support them

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No Evidence For Voter Fraud: A Guide To Statistical Claims About The 2020 Election

by Justin Grimmervia Analysis
Wednesday, February 3, 2021

We focus on fraud allegations with the appearance of statistical rigor. Trump and allies used statistics to claim some election facts would be unlikely if there had been no fraud. The claims fail either because sometimes the “fact” is inaccurate or it is accurate but not surprising. For example, a viral anonymous report claimed Dominion machines added 5.6% to Biden’s vote share.  But, we show that the purported Dominion effect disappears as soon as we control for 2016 results, or make any number of other sensible design choices.

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Comment On “A Simple Test For The Extent Of Voter Fraud With Absentee Ballots In The 2020 Presidential Election”

by Justin Grimmervia Analysis
Tuesday, January 5, 2021

In a recent paper, John Lott Jr. claims to find evidence of anti-Trump fraud in the absentee counting procedure in Fulton County, Georgia, and Allegheny County, Pennsylvania. Using Lott’s own data, we show that his claims are utterly baseless. Lott uses an unusual estimation strategy that suffers from a subtle but fundamental flaw:his conclusions about fraud in Fulton and Allegheny counties are entirely dependent on the completely arbitrary order in which pairs of precincts in other counties are entered in the dataset.


Justin Grimmer: Did Americans’ Racial Attitudes Elect Trump?

interview with Justin Grimmervia Niskanen Center
Thursday, January 16, 2020

Hoover Institution fellow Justin Grimmer discusses the people who voted for President Trump in 2016.