Results from a 2020 field experiment encouraging voting by mail.

Area of Science:

• Political Science
• Public Policy
• Election Administration

Background:

• Voting by mail offers franchise protection but may introduce procedural hurdles for recorded votes.
• Election integrity relies on balancing accessibility with accurate vote recording.
• The COVID-19 pandemic heightened focus on diverse voting methods and their associated challenges.

Purpose of the Study:

• To investigate the impact of mail ballot outreach on voter participation.
• To assess the procedural challenges and policy interventions affecting mail ballot validity.
• To understand the dual effect of mail voting on safeguarding and potentially jeopardizing the franchise.

Main Methods:

• A randomized experiment involving 46,960 Philadelphia registrants before the June 2020 primary election.
• Intervention: Sending postcards encouraging applications for mail-in ballots.
• Analysis of mail ballot casting rates and counting outcomes, considering policy changes.

Main Results:

• The postcard intervention increased the likelihood of casting a mail ballot by 0.4 percentage points (3%).
• A significant portion of these mail ballots were only counted due to a last-minute policy change regarding postmarks.
• Demonstrates both the potential of mail voting to increase participation and the critical role of procedural rules.

Conclusions:

• Outreach efforts can boost mail ballot usage, but procedural safeguards are crucial for ensuring these votes are counted.
• Policy interventions may be necessary to accommodate mail ballots, indicating potential vulnerabilities in the system.
• The study underscores the complex interplay between voting access, procedural integrity, and election outcomes.