Mechanisms of Social Influence: Experimental Evidence from Blood Donations

Last registered on August 19, 2021
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Pre-Trial

Trial Information

General Information

Title
Mechanisms of Social Influence: Experimental Evidence from Blood Donations
RCT ID
AEARCTR-0007266
Initial registration date
February 28, 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
March 01, 2021, 10:41 AM EST

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

Last updated
August 19, 2021, 3:50 AM EDT

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

Locations

Country
Italy
Region

Primary Investigator

Name
Egon Tripodi
Affiliation
University of Essex
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Other Primary Investigator(s)

PI Name
Lorenz Goette
PI Affiliation
University of Bonn
Contact Investigator

Additional Trial Information

Status
In development
Start date
2021-03-01
End date
2021-09-30
Keywords
Behavior, Health
Additional Keywords
social influence, field experiment, blood donations
JEL code(s)
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
In this study we aim to identify the effect of social influence interventions in motivating volunteering behavior, in the setting of blood donations. We develop a novel experimental design to disentangle social pressure from social recognition motives. We vary other aspects of the social influence intervention (communication channel and social proximity of peers) to inform theory as well as practical implementation challenges of behavioral interventions that are implemented at a large scale.
External Link(s)

Registration Citation

Citation
Goette, Lorenz and Egon Tripodi. 2021. "Mechanisms of Social Influence: Experimental Evidence from Blood Donations." AEA RCT Registry. August 19. https://doi.org/10.1257/rct.7266-1.1
Sponsors & Partners

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Experimental Details

Interventions

Intervention(s)
Intervention Start Date
2021-03-01
Intervention End Date
2021-04-16

Primary Outcomes

Primary Outcomes (end points)
Donations in March 2021
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
The experiment has 4 main treatments that are delivered via WhatsApp to donors:
- Social pressure in groups with high social proximity
- Social pressure + social recognition in groups with high social proximity
- Social pressure in groups with low social proximity
- Social pressure + social recognition in groups with low social proximity

Two control groups:
- Baseline message
- No message

Three additional treatment groups:
- Social recognition via Facebook post (sent via Whatsapp)
- Social recognition via Facebook post (sent via email)
- Baseline message (sent via email)
Experimental Design Details
Randomization Method
randomization done in office by a computer
Randomization Unit
group of donors
Was the treatment clustered?
Yes

Experiment Characteristics

Sample size: planned number of clusters
2000 groups of donors
Sample size: planned number of observations
40000 donors
Sample size (or number of clusters) by treatment arms
220
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Supporting Documents and Materials

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IRB

Institutional Review Boards (IRBs)

IRB Name
University of Essex, Ethics Sub Committee 1
IRB Approval Date
2021-02-09
IRB Approval Number
ETH2021-0488
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