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Can nudges encourage people to download the COVID-19 contact tracing apps?
Last registered on March 27, 2021

Pre-Trial

Trial Information
General Information
Title
Can nudges encourage people to download the COVID-19 contact tracing apps?
RCT ID
AEARCTR-0007237
Initial registration date
February 22, 2021
Last updated
March 27, 2021 9:45 PM EDT
Location(s)
Region
Primary Investigator
Affiliation
University of Hyogo
Other Primary Investigator(s)
PI Affiliation
Osaka University
PI Affiliation
Tohoku Gakuin University
Additional Trial Information
Status
On going
Start date
2021-02-15
End date
2021-03-31
Secondary IDs
Abstract
In order to prevent the spread of COVID-19, it is important to find infected people at an early stage as well as encourage people to take preventive actions and social distancing. Contact tracing apps play the role, but voluntary installation is slow. In February 2021, the installation rate in Japan is still about 20%. In this project, we will investigate which kind of nudge-based messages will promote people’s installation. In Study 1, we conduct one online survey experiment toward people who do not refrain from going out. We investigate which nudge-based message is effective for such the people who are not cooperative in preventing the spread of infection. In Study 2, we conduct another online survey experiment toward people, the web search behavior of whom can be traced by a research company. We investigate which nudge-based message draws their interest to contact tracing apps and led to their installation. In both Studies 1 and 2, we evaluate the nudge treatment on self-reported installations in the follow-up survey as well as willingness to install in the initial survey.
External Link(s)
Registration Citation
Citation
Kurokawa, Hirofumi, Fumio Ohtake and Shusaku Sasaki. 2021. "Can nudges encourage people to download the COVID-19 contact tracing apps?." AEA RCT Registry. March 27. https://doi.org/10.1257/rct.7237-1.1.
Experimental Details
Interventions
Intervention(s)
We conduct two online survey experiments. In Study 1, participants are randomly assigned to either of one control group and two treatment groups. One treatment emphasizes the prosocial benefits of the installation, while the other treatment emphasizes its self-benefits. In Study 2, participants are randomly assigned to either of one control group and four treatment groups. In addition to the two treatments mentioned above, the remaining two treatments emphasize the loss of economy and the loss of healthcare, respectively.
Intervention Start Date
2021-02-26
Intervention End Date
2021-03-21
Primary Outcomes
Primary Outcomes (end points)
Self-reported installation behavior of contact tracing apps in the follow-up survey
Primary Outcomes (explanation)
Secondary Outcomes
Secondary Outcomes (end points)
Willingness to install contact tracing apps in the initial survey (intention and willingness to accept)
Web search behavior (only Study 2)
Secondary Outcomes (explanation)
Experimental Design
Experimental Design
We conduct an online survey experiment and a follow-up survey in both Studies 1 and 2. In the online survey, participants are randomly assigned to either one of control group and two treatment groups in Study 1, or one of control group and four treatment groups in Study 2. In the control group, the message on contact tracing apps currently used by the government is displayed. In the treatment groups, the message emphasizing the prosocial benefit of the installation (prosocial treatment), the self-benefits (self-benefits treatment), the loss of economy (economic loss treatment, only in Study 2), and the loss of healthcare (healthcare loss treatment, only in Study 2) are displayed. One week after conducting the online survey, we will conduct a follow-up survey and ask participants to report whether they have installed the apps or not.
Experimental Design Details
Study 1:
Based on the location information obtained by a research company, this survey is conducted on people going out to the downtown area after 8pm, despite the government's warning to refrain from going out. Participants are randomly assigned to either of one control group and two treatment groups (prosocial treatment or self-benefit treatment). We evaluate the nudge treatment effects on self-reported installation behavior in follow-up survey as well as willingness to install in the initial survey.

Study 2:
This survey is conducted on people who can be traced their web search behavior by a research company. Participants are randomly assigned to either of one control group and four treatment groups (prosocial treatment, self-benefit treatment, economic loss treatment, or healthcare loss treatment). We evaluate the nudge treatment effects on self-reported installation behavior in follow-up survey as well as willingness to install in the initial survey. In addition, we investigate how nudge-based messages change the people’s web search behavior.
Randomization Method
Stratified randomization by a survey company in both Studies 1 and 2. The strata are based on age and gender.
Randomization Unit
Individuals in both Studies 1and 2
Was the treatment clustered?
No
Experiment Characteristics
Sample size: planned number of clusters
N/A
Sample size: planned number of observations
Study 1: 3000 individuals (at maximum) Study 2: 5000 individuals (at maximum)
Sample size (or number of clusters) by treatment arms
Study 1: 1000 individuals in the prosocial treatment group, 1000 individual in the self-benefits treatment group, and 1000 individuals in the control group (respectively at maximum)

Study 2: 1000 individuals in the prosocial treatment group, 1000 individual in the self-benefits treatment group, 1000 individual in the economic loss treatment group, 1000 individuals in the healthcare loss treatment, and 1000 individuals in the control group (respectively at maximum)
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
IRB
INSTITUTIONAL REVIEW BOARDS (IRBs)
IRB Name
Graduate School of Economics, Osaka University IRB
IRB Approval Date
2021-02-16
IRB Approval Number
N/A
Post-Trial
Post Trial Information
Study Withdrawal
Intervention
Is the intervention completed?
No
Is 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