Randomized controlled trial on screen time reduction and physical activity

Last registered on February 22, 2021

Pre-Trial

Trial Information

General Information

Title
Randomized controlled trial on screen time reduction and physical activity
RCT ID
AEARCTR-0007209
Initial registration date
February 22, 2021

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
February 22, 2021, 12:02 PM EST

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

Locations

Region

Primary Investigator

Affiliation

Other Primary Investigator(s)

Additional Trial Information

Status
In development
Start date
2021-02-16
End date
2021-04-04
Secondary IDs
Abstract
The aim of this research is to reduce students’ mobile phone screen time and simultaneously increase their physical activity level by providing targets and incentives for a 21-day period. Specifically, we will investigate whether reducing an unwanted behavior such as excessive mobile usage and substituting the gained time with a positive alternative behavior (e.g., walking) is more effective than encouraging a screen time reduction in insolation without a positive substitute behavior. We also investigate consequences of reducing screen time and increasing physical activity on wellbeing and performance measures, such as GPA.
External Link(s)

Registration Citation

Citation
Zimmermann, Laura. 2021. "Randomized controlled trial on screen time reduction and physical activity." AEA RCT Registry. February 22. https://doi.org/10.1257/rct.7209
Sponsors & Partners

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Experimental Details

Interventions

Intervention(s)
Small monetary incentives (2 euros per day during the treatment period of 21 days) combined with a 30% screen time reduction target.
Step count target: baseline step count + 2000 additional steps
Intervention Start Date
2021-02-22
Intervention End Date
2021-03-16

Primary Outcomes

Primary Outcomes (end points)
Daily smartphone screen time
Primary Outcomes (explanation)
Daily smartphone screen time: The daily smartphone usage over the experimental and post-treatment period elicited via screen time apps.
The smartphone usage data collection will be collected by asking subjects to activate a feature in the iPhone (Screen Time) or Android phone (an app called Screen Time downloadable from the Google Play Store). Subjects will take screenshots of their average weekly screen time usage and report their daily screen time via a survey.

Secondary Outcomes

Secondary Outcomes (end points)
Step count
Subjective wellbeing
Academic performance
Secondary Outcomes (explanation)
Step count: objectively measured via the Apple Health app, or for Android users the Google Fit app.
Subjective wellbeing: self-reported measures of satisfaction with health, sleep and general life satisfaction, productivity and smartphone-related anxiety
Academic performance: objectively measured via GPA data from the university

Experimental Design

Experimental Design
Three conditions: Control condition vs. single habit condition vs. combined habit condition
Baseline period: 7 days
Treatment period with targets & incentives: 21 days
Post-treatment period without targets & incentives: 18 days
Experimental Design Details
Three conditions: Control condition vs. single habit condition vs. combined habit condition
Baseline period: 7 days - data collection of baseline screen time and step count
Subjects are randomized into three conditions:
1) Control condition: No incentives or targets for rest of the experimental period
2) Single habit condition: Incentivized 2 euros everyday the screen time is 30% less than the baseline usage
3) Combined habit condition: Incentivized 2 euros everyday the screen time is 30% less than the baseline usage AND step count is higher than baseline step count + 2000 steps.
Treatment period duration: 21 days
Post-treatment: No target or incentives for 18 days, but continued data collection of screen time and step count.


Treatment period with targets & incentives: 21 days
Post-treatment period without targets & incentives: 18 days
Randomization Method
Randomization done in R
Randomization Unit
Randomization at the individual level.
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
1 unit of students
Sample size: planned number of observations
109 students
Sample size (or number of clusters) by treatment arms
Control: 33
Single habit condition: 38
Combined habit condition: 38
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
IRB

Institutional Review Boards (IRBs)

IRB Name
IE Research Committee
IRB Approval Date
2021-01-12
IRB Approval Number
IERC-15/2020-2021

Post-Trial

Post Trial Information

Study Withdrawal

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Intervention

Is the intervention completed?
No
Data Collection Complete
Data Publication

Data Publication

Is public data available?
No

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials