We are happy to announce that all trial registrations will now be issued DOIs (digital object identifiers). For more information, see here.
Group incentives and the demand for preventive care
Last registered on September 19, 2019


Trial Information
General Information
Group incentives and the demand for preventive care
Initial registration date
September 18, 2019
Last updated
September 19, 2019 11:58 AM EDT

This section is unavailable to the public. Use the button below to request access to this information.

Request Information
Primary Investigator
Other Primary Investigator(s)
PI Affiliation
Erasmus School of Economics
Additional Trial Information
In development
Start date
End date
Secondary IDs
Although team incentives are seen as powerful tools to leverage the power of social effects, they have rarely been used to encourage desirable behaviours outside firms. In this study, we investigate whether team incentives are more effective than equivalent individual payments to increase the demand for a preventive visit for cardiovascular diseases (CVDs) in El Salvador. Despite the availability of effective preventive treatments, CVDs are responsible for most deaths and disability worldwide, especially in most Latin American countries where they are a growing epidemic. Yet, in many settings, individuals with a high risk of developing a CVDs remain undiagnosed and those with established CVDs are poorly monitored. In addition to the usual financial and information barriers, behavioural biases may contribute to the low demand for preventive care as CVDs and their risk factors are often asymptomatic. In this study, we seek to increase the demand for preventive CVD check-ups by using financial incentives leveraging the power of social effects in existing networks. In partnership with a micro-finance organisation in San Salvador that offers group loans, we compare team and individual incentives conditional on attending a preventive health check-up, in two alternative designs: a small financial reward and a lottery with a chance to win a large financial prize. We also use detailed information about social networks to study the heterogeneity of effects of alternative schemes.
External Link(s)
Registration Citation
Lagarde, Mylene and Carlos Ruimallo-Herl. 2019. "Group incentives and the demand for preventive care." AEA RCT Registry. September 19. https://doi.org/10.1257/rct.4690-1.0.
Sponsors & Partners

There are documents in this trial unavailable to the public. Use the button below to request access to this information.

Request Information
Experimental Details
Across all arms, group members will be given basic information about CVDs and a voucher for a free preventive check-up. The voucher will come with varying benefits depending on the treatment arm to which the group is randomly assigned:
1. Individual incentive, conditional on doing the preventive check-up
2. Group incentive, conditional on all members of a group doing the check-up.
3. Individual lottery incentive - if s/he wins the lottery, an individual only gets the price if s/he has completed the check-up.
4. Group lottery incentive - if they win the lottery, a group only gets the price if all members have completed the check-up.
5. Control. Individuals who do the check-up receive do not receive any additional benefit.
Intervention Start Date
Intervention End Date
Primary Outcomes
Primary Outcomes (end points)
Utilization of services (take-up of preventive check-up) ;
Health behaviors (smoking, diet, physical activity, health-care seeking, adherence to treatment);
Primary Outcomes (explanation)
Secondary Outcomes
Secondary Outcomes (end points)
• Perceived risk of CVDs
• Perceived need to change lifestyle and health behaviors (smoking, diet, physical activity);
Secondary Outcomes (explanation)
Experimental Design
Experimental Design
Recruitment into the study will take place between October 2019 and January 2020, in the agency of the MFI located in the municipality of Soyapango, a satellite city of the capital San Salvador. All groups including between three to seven members who come to the agency to start a new joint liability microcredit loan, will be eligible to take part in the study. Recruitment of groups into the study will occur on the day their loan is disbursed, when all group members have to be present.

Once they agree to take part, all group members will be interviewed for the baseline survey. At the end of the interview, the group will be randomised to one of the study arms following a randomization sequence generated prior to the start of the fieldwork by the researchers using a web-based randomization tool. We will stratify by group size and group type to ensure a high degree of balance and obtain the desired proportions across treatment groups within each stratum.
The randomized sequences will be concealed from the MFI staff who plan the group appointments so that they cannot manipulate appointments to assign some groups to one treatment or the other. Equally, as groups will be ordered by recruitment date and time, we will easily be able to verify that supervisors follow the allocation sequence.
Experimental Design Details
Not available
Randomization Method
Groups will be randomized following a randomization sequence generated prior to the start of the fieldwork by the researchers using a web-based randomization tool (https://www.sealedenvelope.com/simple-randomiser/v1/lists).
Randomization Unit
Clusters: new loan groups of the micro-finance organization will be randomized to one of the five treatment arms.
Was the treatment clustered?
Experiment Characteristics
Sample size: planned number of clusters
400 loan groups
Sample size: planned number of observations
Approximately 2,000 individuals, members of the loan groups.
Sample size (or number of clusters) by treatment arms
80 loan groups (clusters) in each arm
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
IRB Name
London School of Economics
IRB Approval Date
IRB Approval Number
IRB Name
Comite Nacional de Etica de la Investigacion en Salud
IRB Approval Date
IRB Approval Number