Addressing Public Health Needs by Promoting Prosocial Behaviors Through Social Media

Last registered on August 10, 2021


Trial Information

General Information

Addressing Public Health Needs by Promoting Prosocial Behaviors Through Social Media
Initial registration date
August 06, 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
August 09, 2021, 5:58 PM EDT

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

Last updated
August 10, 2021, 4:27 PM EDT

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



Primary Investigator

UC Berkeley

Other Primary Investigator(s)

Additional Trial Information

Start date
End date
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Social media has the potential to encourage behaviors that improve the health and well-being of society at an unprecedented scale. We examine the impact of Facebook’s blood donation tool on voluntary blood donation in three large countries. Quasi-experimental evidence in the United States indicates that the tool caused an increase in blood donation among all donors (+4.0% [95% CI: .04% to 8.0%]), and particularly among new blood donors (+18.9% [95% CI: 4.7% to 33.1%]) during the tool’s three-month staggered rollout. Longitudinal evidence from Brazil and India indicates that the share of donors who both received a message from the tool and stated they were influenced by Facebook to donate blood increased from 0% to 14.1% [95% CI: 12.1% to 16.2%] in the first year. These findings demonstrate that social media can support public health by encouraging offline prosocial behavior at scale.
External Link(s)

Registration Citation

Harrell, Stephen. 2021. "Addressing Public Health Needs by Promoting Prosocial Behaviors Through Social Media." AEA RCT Registry. August 10.
Experimental Details


Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
Number of donations from all donors and from new donors
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
In 2019, Facebook planned to launch the blood donation tool in the United States. The United States presented a unique measurement opportunity in that there was enough consolidation and coordination within the sector to implement a staggered (partly randomized) rollout of the blood donation tool by geographic location. Furthermore, the blood banks in the United States had a standardized method of collecting ongoing donation data already in place. These attributes make it much more feasible to implement a quasi-randomized (i.e., staggered difference in differences) experimental design in the United States. As with many product launches, however, there were some go-to-market parameters that undermined pure randomization and a select number of cities were launched before the randomized design for the purposes of quality control and to facilitate critical aspects of Facebook’s partnership with blood banks.
Experimental Design Details
Randomization Method
Randomization done in office by a computer
Randomization Unit
State level randomization
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
Sample size: planned number of observations
333 blood donation facilities
Sample size (or number of clusters) by treatment arms
196 treatment group blood donation facilities and 137 control group blood donation facilities
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?
Data Collection Complete
Data Publication

Data Publication

Is public data available?

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials