Using behavioral insights to increase the demand for routine vaccination in low coverage areas in Lebanon: Evidence from a randomized controlled trial

Last registered on October 21, 2019


Trial Information

General Information

Using a Behaviorally-Informed Calendar to Increase the Uptake of Vaccination in Low Coverage Areas in Lebanon: Evidence from a Randomized Controlled Trial
Initial registration date
October 20, 2019

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
October 21, 2019, 10:05 AM EDT

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



Primary Investigator

Nudge Lebanon

Other Primary Investigator(s)

PI Affiliation
Nudge Lebanon
PI Affiliation
Nudge Lebanon

Additional Trial Information

Start date
End date
Secondary IDs
Following a recent measles outbreak, an INGO in partnership with a UN agency supported the Ministry of Public Health (MoPH) launched an immunization program to vaccinate children under the age of 15 in low coverage areas.

The program employs a door-to-door outreach approach to: a) identify dropout children; b) educate and raise awareness of caretakers on the importance of immunization; c) collect and record data via an online application; and d) distribute vaccination vouchers and refer eligible children (dropout children under 15 years old) to the nearest primary healthcare center (PHC) or dispensary.

Despite the successful implementation of the program in 240 cadastres, reaching out to around 193,450 children, several challenges were identified, including ones that have strong behavioral roots (e.g. lack of trust in the quality of vaccines offered by the PHCs and dispensaries; neglect and/or forgetfulness of caretakers to vaccinate their children; lack of awareness that vaccination under the program is free, …). These challenges, among others, have been inhibiting the uptake of vaccination among beneficiaries, even though the vaccination is being offered for free.

To complement this effort, our organisation partnered with the above parties to design, implement and evaluate a nudge to increase the uptake of vaccination. The intervention, which was piloted as a clustered Randomized Controlled Trial (RCT) in seven urban cadastres for a period of two months , consisted of a behaviorally-informed calendar that combined several tools designed to address some of the most common challenges identified through in-depth interviews, focus group discussions and field observations.
External Link(s)

Registration Citation

Makki, Fadi, Ali Osseiran and Andrew Saab. 2019. "Using a Behaviorally-Informed Calendar to Increase the Uptake of Vaccination in Low Coverage Areas in Lebanon: Evidence from a Randomized Controlled Trial." AEA RCT Registry. October 21.
Sponsors & Partners

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Experimental Details


The intervention consisted of a behaviorally informed calendar that combines several tools and levers, including an implementation-intention plan, a commitment device and social endorsement designed to increase the uptake of vaccination compared to those who don’t receive the calendar;designed to address the following challenges:

A. Intention-action gap, namely by asking beneficiaries for a nonbinding commitment to vaccinate their dropout children, and by having them pick the date and location they intend to do so;
B. Negative perception of PHCs and negative social influence, by informing the beneficiaries that many of their neighbors have actually been vaccinating their children at affiliated PHCs or dispensaries for free;
C. Lack of trust in the quality of the vaccines, by highlighting the number of children who have already benefited from vaccinating at a PHC or dispensary since the initiation of the vaccination program; and
D. Lack of awareness that the vaccination services are free, by informing beneficiaries that vaccinating at a PHC or dispensary is free when using an MoPH vaccination waiver.
Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
Proportion of households vaccinating at least one child
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
Target population: Households with dropout children under the age of 15, in high priority areas. These include areas with: a) low immunization coverage, b) measles outbreak and/or c) vulnerable populations.

The target sample consisted of circa 12,000 children (circa 6,000 households) in seven urban cadasters. It included: a) households that have already been referred by outreach teams, but have failed to vaccinate; and b) new households with dropout children.

Randomization: The intervention was evaluated using a clustered randomized controlled trial (RCT) at the level of outreach teams and stratified by cadastre. Thirty-seven outreach teams were involved in the intervention (20 treatment teams; 17 control teams) distributed across three districts and seven cadastres
- District 1: two cadastres
- District 2: three cadastres
- District 3: two cadastres

Touchpoint: The calendar were delivered via the outreach teams during their standard outreach and/or follow up visits during the months of December 2018 and January 2019. Only households that have been assigned to a treatment team received the behavioral intervention (circa 3,000 households).
Experimental Design Details
Randomization Method
Randomisation was completed using STATA 14.0
Randomization Unit
Outreach teams
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
37 outreach teams randomized across 6,108 households
Sample size: planned number of observations
6,108 households
Sample size (or number of clusters) by treatment arms
3,019 (control) and 3089 (treatment)
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
Analysis Plan

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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