Voter registration SMS / mail outreach

What we already know

Voter registration outreach has been tested extensively across US states and UK constituencies. Single-touch SMS and personalized mailers each move registration rates 1–3 percentage points in the eligible-but-unregistered population, at very low per-recipient cost.

Hypothesis

Eligible-but-unregistered residents who receive an SMS and/or mail reminder before the registration deadline will be 1–3 percentage points more likely to register than residents receiving no outreach.

Intervention

Three-arm design: (1) control (no outreach), (2) SMS only ('You may not be registered to vote. Register at [URL] — takes 2 minutes'), (3) SMS + mailer (same SMS plus a printed nonpartisan registration card with deadline highlighted).

Comparison / control

No outreach.

Outcomes

Primary

Voter registration completion by the legal deadline (binary).

Secondary

• Subsequent turnout at the election
• Method of registration (online, by mail, in person)

Required sample size

Computed for α = 0.05, 80% power, balanced allocation. Pick the row whose baseline best matches your jurisdiction, then size at the MDE you can defend.

Need a custom value? Use the sample-size calculator.

Randomization

1. Identify the eligible-but-unregistered list (typically from a vendor with voter-file matching).
2. Stratify by precinct, age band, and primary language.
3. Randomize 1:1:1.
4. Run the campaign 4–8 weeks before the registration deadline.

Data collection

1. Voter-file updates after the registration deadline.
2. Turnout records after the election.

IRB / ethics

Voter mobilization research has a long track record under IRB exempt status, provided the outreach is nonpartisan (does not advocate for candidates or parties) and uses public records. Confirm nonpartisan framing with counsel before launch.

Common pitfalls

• Voter-file matching error: 'eligible-but-unregistered' lists are imperfect. Report match rate.
• Partisan appearance: messages must be strictly nonpartisan. Test the language with diverse readers.
• Cell phone reachability: lower-propensity registrants are more likely to have unreliable cell service. Bounces are not random.

Anchor evidence — registry entries this template draws from

• Voter Registration SMS — Local Authorities

  UK Electoral Commission / Local authorities · United Kingdom · 2022 · Effect: +1.5 to +3 pp registration rate depending on message frame

• Michigan Social Pressure Voting Mailer

  University of Michigan / Yale University · Michigan, USA · 2006 · Effect: Social pressure arm: +8.1 percentage points vs. control; self-disclosure: +4.9 pp; Hawthorne: +2.5 pp; civic duty: +1.8 pp. Social pressure arm produced the largest GOTV effect ever recorded in a randomized study at that time.

Adopt this template

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