Approaches to Healthier Youth Smartphone Use

Last registered on October 07, 2026

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Pre-Trial

Trial Information

General Information

Title

Approaches to Healthier Youth Smartphone Use

RCT ID

AEARCTR-0019832

Initial registration date

October 01, 2026

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 07, 2026, 10:32 AM EDT

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

Locations

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Primary Investigator

Name

Luca Braghieri

Affiliation

Bocconi University

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Other Primary Investigator(s)

Additional Trial Information

Status

In development

Start date

2026-10-01

End date

2027-12-31

Keywords

Other

Additional Keywords

JEL code(s)

Secondary IDs

Prior work

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

Abstract

This project studies how parental limits on smartphone use affect children’s technology use, well-being, and family relationships. We will conduct a large-scale randomized controlled trial with U.S. parent-child dyads in which children are ages 9–13 and use smartphones. The study is motivated by a potential misalignment between the amount of smartphone use parents would prefer for their children and children’s realized use. All participating families will install Qustodio, a parental control application that allows measurement and management of children’s smartphone use. Among families in which children use their smartphones for more than two hours per day and parents prefer lower use, we will randomly assign dyads either to a monitoring-only control group or to a limits treatment. In the treatment group, the study will activate a default two-hour daily screen-time limit and a nighttime restriction; parents may subsequently adjust these limits. We will estimate the effects of the intervention on children’s smartphone use and on outcomes including digital dependence, well-being, sleep, social connectedness, and parent-child relationship quality. Outcomes are measured using administrative smartphone-use data, parent and child surveys, and repeated SMS assessments, with additional administrative and survey follow-up for three months after the intervention.

External Link(s)

Registration Citation

Citation

Braghieri, Luca. 2026. "Approaches to Healthier Youth Smartphone Use." AEA RCT Registry. October 07. https://doi.org/10.1257/rct.19832-1.0

Sponsors & Partners

Experimental Details

Interventions

Intervention(s)

Intervention Start Date

2026-10-19

Intervention End Date

2026-11-23

Primary Outcomes

Primary Outcomes (end points)

The primary downstream endpoints are six pre-specified indices capturing key dimensions of child and family well-being: (1) Child Digital-Dependence Index, measuring the child’s relationship with and dependence on digital devices; (2) Child Well-Being Index, combining measures of subjective well-being, self-esteem, depression, anxiety, and positive affect; (3) Child Sleep-Quality Index; (4) Child Social-Connectedness Index; (5) Parent-Reported Parent–Child Relationship Index; and (6) Child-Reported Parent–Child Relationship Index. These indices combine standardized component measures from parent reports, child reports, and, where applicable, repeated SMS measures, with components oriented so that higher values indicate better outcomes.

We also define primary smartphone-use outcomes measured using Qustodio administrative data: average daily overall screen time, nighttime device use, post-endline screen time, and an index measuring the persistence of screen-time limits during the three-month follow-up period.

Primary Outcomes (explanation)

The attached PAP document describes in detail the construction of the indices.

Secondary Outcomes

Secondary Outcomes (end points)

Secondary Outcomes (explanation)

Experimental Design

We will make this public after the end of data collection.

Experimental Design Details

Not available

Randomization Method

Randomization done by computer. Eligible parent-child dyads will be randomly assigned with equal probability to treatment or control. Randomization will be conducted separately within recruitment waves and stratified by child age, child gender, pre-randomization screen time, and smartphone operating system.

Randomization Unit

The unit of randomization is the parent-child dyad. Eligible dyads are randomized at the individual family level, with assignment stratified by recruitment wave, child age, child gender, pre-randomization screen time, and smartphone operating system.

Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters

Up to 4,000 parent-child dyads. The parent-child dyad is the unit of randomization. Recruitment will continue until we reach a target of 4,000 dyads who complete the study, exhaust available recruitment channels, or exhaust the study budget.

Sample size: planned number of observations

Up to 4,000 parent-child dyads with completed endlines. Because randomization occurs at the parent-child dyad level, the planned number of experimental units is the same as the planned number of clusters. The study collects multiple outcomes and repeated measurements for each dyad, but the primary analyses are conducted at the dyad level.

Sample size (or number of clusters) by treatment arms

Under the primary two-arm design (see attached document for details), dyads are assigned with equal probability to the control group and the limits treatment group. If the study reaches the maximum target of 4,000 completed dyads, this corresponds to approximately 2,000 control dyads and 2,000 limits-treatment dyads.

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

The primary power calculations assume individual-level randomization of parent-child dyads, 80% power, and equal allocation across the limits and control arms. The minimum detectable effect sizes are: - Overall screen time: 0.20 standard deviations (20% of a SD), using a one-sided 5% significance level; this requires approximately 620 dyads total (310 per arm). - Child digital dependence: 0.15 standard deviations (15% of a SD), using a two-sided 5% significance level; this requires approximately 1,396 dyads total (698 per arm). - Child well-being: 0.10 standard deviations (10% of a SD), using a two-sided 5% significance level; this requires approximately 3,140 dyads total (1,570 per arm). These calculations use a simple difference in means and do not incorporate potential precision gains from baseline covariate adjustment, stratification, or wave fixed effects, so they are conservative conservative. There is no additional cluster-design adjustment because the parent-child dyad itself is the unit of randomization.

Supporting Documents and Materials

IRB