Child growth, parental awareness and supplementation – Evidence from Zambia

Last registered on October 28, 2024

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Pre-Trial

Trial Information

General Information

Title

Child growth, parental awareness and supplementation – Evidence from Zambia

RCT ID

AEARCTR-0014624

Initial registration date

October 22, 2024

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 28, 2024, 12:58 PM EDT

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

Locations

Country

Zambia

Region

Multiple

Primary Investigator

Name

Günther Fink

Affiliation

Swiss Tropical and Public Health Institute

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Other Primary Investigator(s)

PI Name

Peter Rockers

PI Affiliation

Boston University

Contact Investigator

PI Name

Doug Parkerson

PI Affiliation

IPA

Contact Investigator

Additional Trial Information

Status

Completed

Start date

2021-04-01

End date

2023-09-30

Keywords

Health

Additional Keywords

child nutrition, child health, growth faltering, stunting, willingness to pay

JEL code(s)

Secondary IDs

Prior work

This trial does not extend or rely on any prior RCTs.

Abstract

Undernutrition remains a major health problem in many settings. We conducted a randomized controlled trial to assess whether the provision of growth charts and food supplements can improve child growth. Households with young children were randomly selected to receive either (1) nutritional supplements alone, (2) growth charts alone or (3) supplements alongside regular monitoring through growth charts. After 18 months of intervention, WTP for continued access to food supplements was measured through home visits offering supplements at randomly determined prices.

External Link(s)

Clinicaltrials.gov registration

Registration Citation

Citation

Fink, Günther, Doug Parkerson and Peter Rockers. 2024. "Child growth, parental awareness and supplementation – Evidence from Zambia ." AEA RCT Registry. October 28. https://doi.org/10.1257/rct.14624-1.0

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Experimental Details

Interventions

Intervention(s)

We test
1) the distribution of growth charts, allowing parents to track children's growth relative to the international reference standards
2) the distribution of small quantity lipid nutrient supplements

in the first phase of the study. In the second phase, we assess households willingness to pay trough a randomized price offer, with prices per sachet (daily dose) ranging between 0 and 3 Zambian Kwachas (20 Zambian Kwacha corresponded to about 1 USD in 2023).

Intervention (Hidden)

Intervention Start Date

2021-10-01

Intervention End Date

2023-06-30

Primary Outcomes

Primary Outcomes (end points)

Phase 1: child growth
Phase 2: willingness to pay for supplements

Primary Outcomes (explanation)

The first objective of the trial is to see if posters or supplements can increase children's growth. The primary outcome used for this part of the trial is children's height-for-age z-score at endline.

The second outcome is household's willingness to pay for sachets - the primary outcome here is a binary indicator for whether or not the household accepts the randomly offered price.

Secondary Outcomes

Secondary Outcomes (end points)

Secondary Outcomes (explanation)

Experimental Design

The first phase of the trial is designed as cluster-randomized trial, with each cluster corresponding to an enumeration area. Clusters will be randomly assigned to either 1) control 2) growth charts only 3) supplements only 4) posters and supplements.

After completion of the phase 1 trial, all households will be offered supplements at a randomly selected price (after completion of the endline survey). A subsample of households residing in Lusaka will get a second offer to purchase supplements at a second randomly selected price.

Experimental Design Details

Randomization Method

We used min-max randomization for the first phase, and a simple random number draw for the random selection of prices.

Randomization Unit

Phase 1: clusters/enumeration areas
Phase 2: households

Was the treatment clustered?

Yes

Experiment Characteristics

Sample size: planned number of clusters

282 clusters/enumeration areas

Sample size: planned number of observations

2400 caregiver-child dyads

Sample size (or number of clusters) by treatment arms

Phase 1: 70 clusters, 600 children per arm
Phase 2: all households followed up

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

The study was powered to detect this 0.25 HAZ difference between any of the three intervention arms and the control arm with probability 0.9, assuming α=0.05, 15% attrition between baseline and endline and a design effect of 2.

Supporting Documents and Materials

IRB