Field experiment in collaboration with Italian NGO to study short and long term effects of social recognition.
Intervention Start Date
2019-10-29
Intervention End Date
2020-11-30
Primary Outcomes (end points)
Blood donations made in November 2019
Plasma donations made in November 2019
Blood donations made in November 2020
Plasma donations made in November 2020
Primary Outcomes (explanation)
To assess the short [long] term effects of visibility incentives on blood (plasma) donations we compare blood (plasma) donations made in November 2019 [2020] between treatments ii and iv (iii and v).
Secondary Outcomes (end points)
Secondary Outcomes (explanation)
We will look into whether treatment effects are stronger - for women than for men;
- for inactive donors (those who have not donated in the last 24 months) than for active donors.
Experimental Design
The experiment randomizes whether registered blood donors are offered a public acknowledgment on social media for donating blood in a certain period of time.
Experimental Design Details
This is a between-subjects experiment. In each treatment, a blood donor receives a personalized email in which we vary part of the contents.
The experiment features 5 main treatments:
(i) Control: No email.
(ii) Encouragement Blood: Donor is invited to make a whole blood donation in the coming month.
(iii) Encouragement Plasma: Donor is invited to make a plasma donation in the coming month.
(iv) Visibility Blood: Donor is invited to make a whole blood donation in the coming month. As an incentive, donors are told that for this donation the NGO will be thanking them publicly through its official social media channels.
(v) Visibility Plasma: Donor is invited to make a whole plasma donation in the coming month. As an incentive, donors are told that for this donation the NGO will be thanking them publicly through its official social media channels.
For all treatments (excluding Control) we cross-randomize whether information is provided about the current level of local shortages of blood supply.
Randomization works as follows. Main treatments are divided into three groups: No visibility incentives (i-iii), Visibility incentives for Blood (iv), and Visibility incentives for Plasma (v). We randomize the 65 selected local branches of the NGO into one of these three groups.
In the No visibility incentives group, randomization of the main treatment is done at the individual level. Cross-randomization of secondary information treatment is done at the individual level.
Randomization Method
randomization done in office by a computer
Randomization Unit
Some of the treatments are randomized across clusters, and some treatments are randomized within clusters.
Was the treatment clustered?
Yes
Sample size: planned number of clusters
65 local branches of the NGO
Sample size: planned number of observations
about 15,000 blood donors
Sample size (or number of clusters) by treatment arms
For the main treatments, we have about 20 clusters per treatment with about 5,000 donors each.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)