An Informational Letter From the Federal Government Increases Naturalization Submissions

Last registered on May 27, 2025
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Pre-Trial

Trial Information

General Information

Title
An Informational Letter From the Federal Government Increases Naturalization Submissions
RCT ID
AEARCTR-0016083
Initial registration date
May 24, 2025

Initial registration date is when the trial was registered.

It corresponds to when the registration was submitted to the Registry to be reviewed for publication.

First published
May 27, 2025, 10:31 AM EDT

First published corresponds to when the trial was first made public on the Registry after being reviewed.

Locations

Country
United States of America
Region

Primary Investigator

Name
Oded Gurantz
Affiliation
University of Missouri
Contact Primary Investigator

Other Primary Investigator(s)

Additional Trial Information

Status
Completed
Start date
2023-10-01
End date
2024-06-30
Keywords
Behavior, Governance, Other
Additional Keywords
Citizenship, Naturalization
JEL code(s)
D90, J15, J18, K37
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
Citizenship offers enhanced opportunities for immigrants, but the complex naturalization process can be a barrier. We evaluate a pre-registered, large-scale randomized trial that tested the impact of a low-cost informational letter encouraging potentially eligible Lawful Permanent Residents (LPRs) to apply for naturalization.
External Link(s)

Registration Citation

Citation
Gurantz, Oded. 2025. "An Informational Letter From the Federal Government Increases Naturalization Submissions." AEA RCT Registry. May 27. https://doi.org/10.1257/rct.16083-1.0
Sponsors & Partners
Experimental Details

Interventions

Intervention(s)
This study evaluated a pre-registered randomized control trial to quantify the impact of a low-cost informational letter sent from the federal government that encourages eligible Lawful Permanent Residents (LPRs) to apply for naturalization. The evaluation was conducted by the Department of Homeland Security’s (DHS) United States Citizenship and Immigration Services (USCIS) as part of its goals to expand citizenship and promotion efforts by making tools and resources available to people navigating the process. USCIS identified from its records
1,861,178 persons who had achieved LPR status between six and nine years prior and had not previously applied for citizenship. It then mailed an letter to a randomly selected 300,000 LPRs from this group, encouraging them to apply for U.S. citizenship, while the remaining LPRs in the control group were not mailed the letter. This letter contained information about how to complete the naturalization application
process, emphasized the benefits of naturalization, provided statistics about the success rates of passing the requisite exams for naturalization, and gave recipients easy access to a web page where all this information was aggregated. We then evaluated whether the LPRs submitted the N-400 naturalization application form within a follow-up period of six to eight months.
Intervention (Hidden)
Intervention Start Date
2023-10-01
Intervention End Date
2023-12-31

Primary Outcomes

Primary Outcomes (end points)
Submission of an N-400 Form for application for U.S. citizenship
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
With 1,861,178 individuals and 300,000 letters, the treatment assignment probability was 16.12%. Individuals were stratified into 100 groups based on years since LPR status, class of admission, and region of birth, then randomized within these strata at a 16.12% treatment rate. Strata sizes varied, with a median of 16,720 and a range from just under 300 to over 49,000. The 300,000 randomly selected individuals were mailed letters in a staggered rollout from late October to early December 2023. Ultimately, 89.3% of the treatment group letters were delivered.
Experimental Design Details
Randomization Method
In Stata via runiform and seed
Randomization Unit
Individual
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
Almost 1.9 million individuals
Sample size: planned number of observations
Almost 1.9 million individuals
Sample size (or number of clusters) by treatment arms
Almost 1.9 million individuals
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
~0.3 percentage points
Supporting Documents and Materials
IRB

Institutional Review Boards (IRBs)

IRB Name
IRB Approval Date
IRB Approval Number
Analysis Plan

Post-Trial

Post Trial Information

Study Withdrawal

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Intervention

Is the intervention completed?
No
Data Collection Complete
Data Publication

Data Publication

Is public data available?
No

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials