Experimental Evidence on the Impact of Occupational Inequality on Union Support

Last registered on June 30, 2025
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Pre-Trial

Trial Information

General Information

Title
Experimental Evidence on the Impact of Occupational Inequality on Union Support
RCT ID
AEARCTR-0016278
Initial registration date
June 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
June 30, 2025, 6:04 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
Julia Gilman
Affiliation
Massachusetts Institute of Technology
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Other Primary Investigator(s)

PI Name
Zoe Cullen
PI Affiliation
Harvard Business School
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PI Name
Nina Roussille
PI Affiliation
Massachusetts Institute of Technology
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PI Name
Barbara Biasi
PI Affiliation
Yale School of Management
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Additional Trial Information

Status
Completed
Start date
2023-08-11
End date
2025-06-23
Keywords
Labor
Additional Keywords
inequality, collective bargaining, pay transparency
JEL code(s)
J31, J5, D83, D84, C93
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
We seek to understand how wage inequality impacts workers' union support through an information provision experiment. In the context of the 2023 Hollywood writers' strike, we distribute a pay report to writers that reveals larger than expected gaps in pay. We randomize the order in which we display this report and elicit union support.
External Link(s)

Registration Citation

Citation
Biasi, Barbara et al. 2025. "Experimental Evidence on the Impact of Occupational Inequality on Union Support." AEA RCT Registry. June 30. https://doi.org/10.1257/rct.16278-1.0
Sponsors & Partners
Experimental Details

Interventions

Intervention(s)
We show a pay report that includes the mean, median, and maximum pay rate (in terms of percent above the union minimum) by gender
Intervention (Hidden)
Intervention Start Date
2023-08-11
Intervention End Date
2023-08-13

Primary Outcomes

Primary Outcomes (end points)
Union support
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Heterogeneity by productivity, tenure, and gender
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
Our survey includes only 1 question (our union support outcome) as well as our treatment (the pay report). We randomize the order in which respondents see the question and the pay report. The treatment group are respondents who see the pay report, and then answer the union support question. The control group are respondents who answer the union support question, and then see the pay information.
Experimental Design Details
Randomization Method
Qualtrics
Randomization Unit
Individual
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
310
Sample size: planned number of observations
310
Sample size (or number of clusters) by treatment arms
170 treatment, 140 control
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Supporting Documents and Materials
IRB

Institutional Review Boards (IRBs)

IRB Name
Study has received IRB approval. Details not available.
IRB Approval Date
Details not available
IRB Approval Number
Details not available
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