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Nudging Take-up of the Earned Income Tax Credit in California

Last registered on April 21, 2020


Trial Information

General Information

Nudging Take-up of the Earned Income Tax Credit in California
Initial registration date
April 17, 2020

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
April 21, 2020, 11:30 AM EDT

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



Primary Investigator


Other Primary Investigator(s)

PI Affiliation
University of California Berkeley
PI Affiliation
University of California Berkeley
PI Affiliation
University of California Berkeley

Additional Trial Information

Start date
End date
Secondary IDs
The federal Earned Income Tax Credit (EITC) is the largest means-tested cash transfer program in the US, distributing more than $60 billion to low-income households annually. Nevertheless, an estimated one-fifth of households eligible for the EITC do not claim it. Drawing on previous evidence suggesting that low-cost behavioral interventions can address some of the administrative burdens that limit take-up, we ran six pre-registered field experiments testing the effect of outreach aimed at increasing claiming of the California and federal EITC. These studies were conducted in collaboration with the California tax and social service agencies and with a large NGO that conducts statewide outreach, and collectively involved more than one million subjects. We varied the content, design, messenger, and mode of messages within and across these studies. We find no evidence that any of our nudges affected households’ likelihood of filing a tax return or claiming the credit. While our messages spurred high levels of engagement with the outreach material, we conclude that even the most behaviorally informed outreach efforts cannot overcome the barriers to EITC claiming faced by low-income households who do not file returns.

Registration Citation

Linos, Elizabeth et al. 2020. "Nudging Take-up of the Earned Income Tax Credit in California." AEA RCT Registry. April 21.
Experimental Details


Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
- Indicator for the presence of a matched return
- Indicator for the presence of any EITC claim
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
See analysis plans for more information:
Study 1:
Studies 2, 3, and 4:
Study 5:
Study 6:
Experimental Design Details
Randomization Method
by computer
Randomization Unit
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
Study 1: 639,244 households
Study 2: 96,370 households
Study 3: 1,084,018 households
Study 4: 204,285 households
Study 5: 38,093 households
Study 6: 47,104 households
Sample size: planned number of observations
Study 1: 648,890 individuals Study 2: 114,192 individuals Study 3: 1,236,174 individuals Study 4: 206,022 individuals Study 5: 109,046 households Study 6: 121,085 individuals
Sample size (or number of clusters) by treatment arms
Study 1: 200,000 control; remainder treatment
Study 2: 10,000 to each treatment arm; remainder control
Study 3: 20% to each treatment arm; 20% control
Study 4: 15,000 to each treatment group; remainder control
Study 5: 50% treatment; 50% control
Study 6: 25% to each treatment arm; 25% control
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)

Institutional Review Boards (IRBs)

IRB Name
IRB Approval Date
IRB Approval Number


Post Trial Information

Study Withdrawal

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Is the intervention completed?
Intervention Completion Date
December 31, 2019, 12:00 +00:00
Data Collection Complete
Data Collection Completion Date
December 31, 2020, 12:00 +00:00
Final Sample Size: Number of Clusters (Unit of Randomization)
Was attrition correlated with treatment status?
Final Sample Size: Total Number of Observations
Final Sample Size (or Number of Clusters) by Treatment Arms
Data Publication

Data Publication

Is public data available?

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials

Published paper
Linos, Elizabeth, Allen Prohofsky, Aparna Ramesh, Jesse Rothstein, and Matthew Unrath. 2022. "Can Nudges Increase Take-Up of the EITC? Evidence from Multiple Field Experiments." American Economic Journal: Economic Policy, 14 (4): 432-52. DOI: 10.1257/pol.20200603