Applying Behavioral Insights for Encouraging Parents to Vaccinate their Daughters against HPV in Colombia

Last registered on July 08, 2022

View Trial History

Pre-Trial

Trial Information

General Information

Title

Applying Behavioral Insights for Encouraging Parents to Vaccinate their Daughters against HPV in Colombia

RCT ID

AEARCTR-0009705

Initial registration date

July 05, 2022

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

July 08, 2022, 9:48 AM EDT

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

Locations

Country

Colombia

Region

Primary Investigator

Name

Julian Peña

Affiliation

Universidad del Rosario

Contact Primary Investigator

Other Primary Investigator(s)

PI Name

Stanislao Maldonado

PI Affiliation

Universidad del Rosario

Contact Investigator

Additional Trial Information

Status

On going

Start date

2022-04-25

End date

2022-09-30

Keywords

Behavior, Health

Additional Keywords

JEL code(s)

Secondary IDs

Prior work

This trial is based on or builds upon one or more prior RCTs.

Abstract

We conducted a text SMS campaign leveraging the lessons from behavioral sciences to increase vaccine take-up against the Human Papillomavirus (HPV) in Colombia. In particular, these messages integrate behavioral insights in dimensions related to altruism, warm-glow giving, default options, reminders, and beliefs.

External Link(s)

Registration Citation

Citation

Maldonado, Stanislao and Julian Peña. 2022. "Applying Behavioral Insights for Encouraging Parents to Vaccinate their Daughters against HPV in Colombia." AEA RCT Registry. July 08. https://doi.org/10.1257/rct.9705-1.0

Sponsors & Partners

Experimental Details

Interventions

Intervention(s)

The study included three types of experiments designed to improve the HPV vaccination rates in this setting. The first type of experiment focuses on altruism and its distinction with warm-glow giving. The second uses soft default options and some insights from Milkman et al. (2021). The third may aim to correct parents' beliefs about the HPV vaccine. Each experiment included two fixed components in its messages: the name of the person to whom the message was sent and the message's sender. We added the fixed components to make the message more personalized, as other settings have shown it to be effective. For the population of unvaccinated girls we implemented all three types of experiments. In contrast, only the default options and milkman insights were applied to girls with incomplete HPV vaccination schedules. The reason for this was that there was not enough sample for girls with incomplete HPV vaccination schedules to conduct further experiments.

Intervention Start Date

2022-05-04

Intervention End Date

2022-06-11

Primary Outcomes

Primary Outcomes (end points)

The primary outcome is a categorical variable that indicates whether a parent’s daughter is vaccinated against HPV during the SMS campaign window (6 weeks) or during the 6 weeks after the end of the intervention.

Primary Outcomes (explanation)

This outcome will be constructed from administrative records. The information on the vaccines, this is uploaded to the application (PAIWEB) by the health providers.

Secondary Outcomes

Secondary Outcomes (end points)

None

Secondary Outcomes (explanation)

None

Experimental Design

All the interventions described above were randomized at the individual level using a randomized block design. Specifically, participants were divided into blocks according to their location (Bogotá or outside Bogotá) and the girl's age.

All the experiments were implemented simultaneously.

Experimental Design Details

Randomization Method

Randomization by a computer using the rerandomization algorithm proposed by Morgan and Rubin (2012).

Randomization Unit

girl

Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters

None.

Sample size: planned number of observations

The target sample for the experiments with unvaccinated girls is 16,538 observations. The target sample for the experiments with girls with incomplete vaccination schedules is 5,907.

Sample size (or number of clusters) by treatment arms

The sample size by treatment arm is 1273 observations for the experiments with unvaccinated girls.

The sample size by treatment arm is 985 observations for the experiments with girls with incomplete vaccination schedules.

Minimum detectable effect size for main outcomes (accounting for sample design and clustering)

We estimated the minimum sample size for each experiment assuming an individual randomized design with an effect size of 4.25 percentage points, 90% power, and a Chi-Square test for difference of proportions at a 5% significance level. Because each experiment has up to 6 treatment arms, we adjusted for multiple testing using a Bonferroni correction for up to 6 comparisons in each experiment. Under these assumptions, the minimum sample size for each experiment is 5,858 subjects.

Supporting Documents and Materials

IRB