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Child human capital production: A field experiment in the Solomon Islands
Last registered on August 20, 2019


Trial Information
General Information
Child human capital production: A field experiment in the Solomon Islands
Initial registration date
August 20, 2019
Last updated
August 20, 2019 8:09 PM EDT
Primary Investigator
Other Primary Investigator(s)
PI Affiliation
University of New South Wales
PI Affiliation
Ecole Normale Superieure
PI Affiliation
University of Technology Sydney
PI Affiliation
University of San Francisco
Additional Trial Information
On going
Start date
End date
Secondary IDs
We introduce and test an early learning intervention on child-directed speech in the Solomon Islands, which aims to: (i) estimate the relative contributions of parental inputs in the child human capital production function, and (ii) identify the channels through which early childhood interventions can be effective. We provide parents with information and learning materials intended to stimulate child-directed speech. We then measure short-run (within days of the intervention) and medium-run (after 1 year) effects of the intervention on speech outcomes.
External Link(s)
Registration Citation
Cassar, Alessandra et al. 2019. "Child human capital production: A field experiment in the Solomon Islands." AEA RCT Registry. August 20. https://doi.org/10.1257/rct.4116-2.0.
Experimental Details
We provide parents with information about the importance of child directed speech. They are also given materials they can use with their children to stimulate child directed speech at home. A control group receives no intervention. We measure speech outcomes before and after the intervention and compare them across treatment v. control.
Intervention Start Date
Intervention End Date
Primary Outcomes
Primary Outcomes (end points)
Words spoken to the child by adults and children. Utterances by the child. Conversational turns.
Primary Outcomes (explanation)
Secondary Outcomes
Secondary Outcomes (end points)
Parental beliefs about the returns to child directed speech. Parental investment in children.
Secondary Outcomes (explanation)
Experimental Design
Experimental Design
We assign treatment at the village level. In each village, we ask village leaders to assemble a community meeting, where we randomly select participants via public lottery. The selection criteria for attending the meeting is couples (male and female partners who consider themselves to be in a committed relationship) between the ages of 20 and 45, who have at least one child between the ages of 18 months and 3 years. We then randomly select 5 couples (10 participants) and their respective child to participate in the intervention by pulling numbers out of an urn and announcing them publicly in the community meeting.

We will conduct a follow-up 1 year after the initial intervention.
Experimental Design Details
Randomization Method
Treatment (village level) randomization done in office by a computer. Participants within each village selected via public lottery.
Randomization Unit
Was the treatment clustered?
Experiment Characteristics
Sample size: planned number of clusters
50 villages.
Sample size: planned number of observations
50 villages x 5 couples per village = 250 couples. 1 child per couple = 250 children. 2 parents per child = 500 parents.
Sample size (or number of clusters) by treatment arms
14 control villages and 36 treatment villages.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Informed by data from Weber et al. (2017) study in Senegal. We assume 0.8 power, alpha=0.05, and 25% correlation between clusters. First main outcome is words spoken to the child by the parent in a 5-minute session. Baseline mean of 228 words (SD=151). MDE=42% increase. Second main outcome is utterances by the child in a 5-minute session. Baseline mean of 35.5 utterances (SD=15). MDE=27% increase.
IRB Name
University of New South Wales HREC Executive
IRB Approval Date
IRB Approval Number
Analysis Plan

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Post Trial Information
Study Withdrawal
Is the intervention completed?
Is data collection complete?
Data Publication
Data Publication
Is public data available?
Program Files
Program Files
Reports, Papers & Other Materials
Relevant Paper(s)