AEA RCT Registry

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Field	Before	After
Trial Status	in_development	on_going
Last Published	August 06, 2024 01:27 PM	August 11, 2024 05:25 AM
Intervention (Public)	Female adolescents aged 12-16 are randomized into three types of vouchers. Participants will receive the same voucher twice a week over a three week period.	Classes of female adolescents aged 12-16 are randomized into three types of vouchers. Participants will receive the same voucher twice a week over a three week period.
Experimental Design (Public)	Subjects are randomly allocated to the three experimental voucher conditions. We will collect baseline survey and controlled meal choices, as well as two rounds of follow-up controlled meal choices. We will also collect body height and weight at baseline, as well as weights at follow ups. We will also collect food diaries during the intervention period.	Classes are randomly allocated to the three experimental voucher conditions. We will collect baseline survey and controlled meal choices, as well as two rounds of follow-up controlled meal choices. We will also collect body height and weight at baseline, as well as weights at follow ups. We will also collect food diaries during the intervention period.
Randomization Method	Randomization is done in office using Stata based on the baseline data we collected. Stratified randomization by class is conducted.	Randomization is done in office using Stata 18.5 based on the baseline data we collected. We initially registered an individual randomization stratified by class. After collecting the baseline data, we observed a low ICC of 0.01052 at class level, which allowed us for a cluster randomization (MDEs of individual and clustered randomization are qualitatively similar). We thus updated our power calculations below and randomized 70 classes (instead of individuals) into control, treatment 1 and treatment 2 stratified by school. This change in randomization approach is meant to better guard against spillovers and make administration of vouchers easier. After randomizing classes into three groups, we checked balance on the meal choice (primary outcome), as well as age, BMI for age, weight, height and class size. We detected no significant differences at conventional levels.
Randomization Unit	We randomize at the student level.	We randomize classes stratified by school.
Was the treatment clustered?	No	Yes
Planned Number of Clusters	Not applicable due to individual randomization.	70 classes located in 5 schools as included in baseline data.
Planned Number of Observations	1000 students	1011 students as included in baseline data.
Sample size (or number of clusters) by treatment arms	The targeted 1000 participants are allocated to the three groups in a balanced way: 333 in control group, 334 students in treatment 1 and 333 students in treatment 2.	The targeted 1011 baseline participants in 70 classes in 5 schools are allocated to the three groups in a roughly balanced way (stratified by schools): 327 students (23 classes) in control group, 342 students (23 classes) in treatment 1 (restricted voucher) and 342 students (24 classes) in treatment 2 (voucher with choice).
Power calculation: Minimum Detectable Effect Size for Main Outcomes	We performed power calculations as follows: Based on relevant Indonesian Family Life Survey data, we assume control is eating healthy foods (leafy greens) 2 times a week = 2/7 = 0.285. Setting 80% power and a MDE of 0.7 servings of vegetables per week more, we require 1000 respondents.	Using our baseline data we performed an updated power calculation for a clustered randomization (instead of an individual one as planned). Taking the baseline healthy choice of 0.2275, an average of 14 kids per class, 23 classes in control and treatment each, we use the following command in STATA: power twoproportions 0.2275, m1(14) m2(14) rho(0.01052) power(0.8) k1(23) k2(23). We are powered for a MDE of 0.1055. Inclusion of covariates including baseline meal choice may further increase power.