Small quasi-cash rewards for plasma donations

Last registered on September 12, 2024
View Trial History

Pre-Trial

Trial Information

General Information

Title
Small quasi-cash rewards for plasma donations
RCT ID
AEARCTR-0014281
Initial registration date
August 30, 2024

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
September 12, 2024, 5:21 PM EDT

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

Locations

Country
Belgium
Region
Flanders

Primary Investigator

Name
Stijn Bruers
Affiliation
KU Leuven
Contact Primary Investigator

Other Primary Investigator(s)

PI Name
Erwin Ooghe
PI Affiliation
KU Leuven
Contact Investigator
PI Name
Erik Schokkaert
PI Affiliation
KU Leuven

Additional Trial Information

Status
Completed
Start date
2021-11-01
End date
2023-10-31
Keywords
Behavior, Health
Additional Keywords
JEL code(s)
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
The randomized field experiment involves twelve donation centers of the Belgian Red Cross-Flanders to study the impact of information provision and extra rewards for plasma donations. As a normal practice, donors receive one thank-you coupon (worth $1.5) for a blood donation and two coupons for a plasma donation. Those rewards are not mentioned in the monthly newsletter. In the experiment, the donation centers are randomly allocated to three groups: four are allocated to a control group, four to the information treatment group and the remaining four to the reward treatment group. For a period of nine months (the information period) the monthly newsletter of the information and reward group donation centers explicitly mention the rewards for blood and plasma donations. During six of those nine months (the reward period), donors at donation centers of the reward group receive an extra reward for plasma donations (i.e. three instead of two coupons). The hypotheses to be tested are: does informing donors about the rewards influence their donation rates? Does the extra reward for plasma donation increases the plasma donation rate? Is there a shift from blood to plasma donations when plasma donors receive an extra reward? Do donors change the timing or location of their donations when some donation centers give more rewards for plasma donation during some periods?
External Link(s)

Registration Citation

Citation
Bruers, Stijn, Erwin Ooghe and Erik Schokkaert. 2024. "Small quasi-cash rewards for plasma donations." AEA RCT Registry. September 12. https://doi.org/10.1257/rct.14281-1.0
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Experimental Details

Interventions

Intervention(s)
Some newsletters send to donors contain, during a period of nine months, information about rewards for blood and plasma donation.
At some donation centers, during a period of six months, donors receive an extra reward for plasma donation (three instead of two thank-you coupons).
Intervention Start Date
2022-10-01
Intervention End Date
2023-06-30

Primary Outcomes

Primary Outcomes (end points)
Donation rates (number of blood and plasma donations per donor per month)
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
As a normal practice at donation centers of the Belgian Red Cross-Flanders, donors receive one thank-you coupon (worth $1.5) for a blood donation and two coupons for a plasma donation. Those rewards are not mentioned in the monthly newsletter. In the experiment, the twelve donation centers of the Belgian Red Cross-Flanders are randomly allocated to three groups: four are allocated to a control group, four to the information treatment group and the remaining four to the reward treatment group. For a period of nine months (the information period) the monthly newsletter of the information and reward group donation centers explicitly mention the rewards for blood and plasma donations. During six of those nine months (the reward period), donors at donation centers of the reward group receive an extra reward for plasma donations (i.e. three instead of two coupons).
Experimental Design Details
Randomization Method
Using cluster analysis based on monthly levels and variations of blood and plasma donations, the twelve donation centers are clustered in four groups of three centers each. The donation centers within a cluster have similar levels and variations of donations (hence are roughly equal in size). For each cluster, one of its three donation centers is randomly allocated to the control group, one is randomly allocated to the information treatment group and the third is allocated to the reward group. In this way, the twelve donation centers are randomly allocated to three groups of donation centers. All donors who donate at the same donation center are treated the same (receive the same newsletter and the same rewards).
Randomization Unit
Donation center level
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
12 donation centers
Sample size: planned number of observations
200.000 donors, 24 months
Sample size (or number of clusters) by treatment arms
4 donation centers control, 4 donation centers information group, 4 donation centers reward group
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Supporting Documents and Materials
IRB

Institutional Review Boards (IRBs)

IRB Name
KU Leuven PRET
IRB Approval Date
2023-07-13
IRB Approval Number
G-2022-4948
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