Using Personalized Letters and Emails to Increase Health Insurance Take-up in California’s ACA Marketplace

Last registered on June 20, 2022

Pre-Trial

Trial Information

General Information

Title
Using Personalized Letters and Emails to Increase Health Insurance Take-up in California’s ACA Marketplace
RCT ID
AEARCTR-0007842
Initial registration date
June 21, 2021

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
June 22, 2021, 10:08 AM EDT

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

Last updated
June 20, 2022, 7:17 PM EDT

Last updated is the most recent time when changes to the trial's registration were published.

Locations

Primary Investigator

Affiliation
Covered California

Other Primary Investigator(s)

PI Affiliation
Covered California

Additional Trial Information

Status
Completed
Start date
2021-05-27
End date
2021-12-31
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
With the passage of the American Rescue Plan (ARP) in March 2021, more consumers than ever before are now eligible for free health insurance coverage across the ACA Marketplaces. But many individuals may not be aware of the new subsidies, or of their eligibility for Cost-Sharing Reduction (CSR) Silver plans. This project's goal is to examine the effects of personalized letters and email reminders.
External Link(s)

Registration Citation

Citation
Feher, Andrew and Emory Wolf. 2022. "Using Personalized Letters and Emails to Increase Health Insurance Take-up in California’s ACA Marketplace." AEA RCT Registry. June 20. https://doi.org/10.1257/rct.7842
Experimental Details

Interventions

Intervention(s)
In May 2021, during a Special Enrollment Period (SEP) in California's ACA Marketplace, we identified 44,000 households who submitted a Covered California application for the 2021 coverage year, were found eligible for a $1 CSR Silver 94 plan but yet to enroll. We then randomly assigned households to one of three arms: (1) a Control group assigned to receive no letter or emails during the month of June 2021, a (2) a Generic outreach group assigned to receive a letter and two email reminders about the availability of $1 plans, or (3) a Personalized outreach group assigned to receive a letter and two email reminders informing them that they are eligible for a $1 PMPM Enhanced Silver 94 plan.

The second intervention took place during the 2022 Open Enrollment Period (OEP). At the end of November 2021, we identified 11,245 households with an email address who submitted an application for the 2022 coverage year, were found eligible for a $0 CSR Silver 94 plan but not yet enrolled. We then randomly assign households to either a control group or a personalized outreach group that received a letter along with two email reminders informing them that they are eligible for a $0 Enhanced Silver 94 plan.
Intervention Start Date
2021-06-07
Intervention End Date
2021-06-30

Primary Outcomes

Primary Outcomes (end points)
This study includes four outcomes of interest for each of the experiments: indicators for (1) whether a household enrolled in ACA coverage by the end of the intervention period, (2) whether a household selected a CSR Silver plan, (3) whether a household was paying $1/month or $0 and (4) retention. For the SEP experiment, retention is defined as whether a household was still enrolled in December 2021 (four months after the end of the intervention), and for the OEP experiment, whether the household was still enrolled in May 2022 (four months after the end of Open Enrollment).
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
Households in the SEP experiment were randomly assigned to one of three arms: (1) a Control group, (2) a Generic outreach group, or (3) a Personalized outreach group.

Households in the OEP experiment were randomly assigned to one of two arms: (1) a Control group or (2) a Personalized outreach group.
Experimental Design Details
Randomization Method
We used Stata to carry out the randomization.
Randomization Unit
Random assignment occurs at the household-level.
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
N/A
Sample size: planned number of observations
44,000 households in the SEP experiment and 11,245 households in the OEP experiment.
Sample size (or number of clusters) by treatment arms
SEP experiment: 11,000 were assigned to the Control group, 16,500 were assigned to the Generic treatment group and 16,500 were assigned to the Personalized treatment group.

OEP experiment: 5,622 were assigned to the Control group and 5,623 were assigned to a personalized treatment group.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
We expect the baseline health insurance take-up rate to be under 5 percent, based on prior evaluations among applicants referred by the Medicaid eligibility system. In a pairwise comparison (e.g. Control vs. Personalized treatment), we are powered at the 80% level to detect a 0.5 percentage point difference in health insurance take-up rates.
IRB

Institutional Review Boards (IRBs)

IRB Name
California Health and Human Services Agency: Office of Human Research Protections
IRB Approval Date
2021-05-27
IRB Approval Number
N/A

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