In a concise new paper published by Harvard’s Ash Center for Democratic Governance and Innovation, Tova Wang and Jose Altamirano analyze trends in mail ballot rejection rates in 2020. Were mail ballots rejected at a higher rate in 2020 compared to previous years? What impact did policy changes, the political environment, and voter outreach have on mail ballot rejection rates in such an extraordinary election year?

Key findings include:

• Mail ballot rejection rates decreased in most states in 2020 compared to 2018, and a number of states saw a consistent drop from 2016 through 2020.

• Certain states that adapted their voting laws to make mail voting more accessible in 2020, particularly in the South, saw especially pronounced changes in rejection rates.

• States that implemented mail ballot policies, including ballot curing, increased ease of access when returning mail ballots at Boards of Elections, early voting sites, drop boxes, and ballot tracking, saw lower rejection rates than those that didn’t.