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Face Mask Mandate and Compliance with Physical Distancing Recommendations During the COVID-19 Pandemic
Last registered on May 13, 2020

Pre-Trial

Trial Information
General Information
Title
Face Mask Mandate and Compliance with Physical Distancing Recommendations During the COVID-19 Pandemic
RCT ID
AEARCTR-0005831
Initial registration date
May 11, 2020
Last updated
May 13, 2020 3:45 PM EDT
Location(s)
Region
Primary Investigator
Affiliation
University of Groningen
Other Primary Investigator(s)
PI Affiliation
Berlin School of Economics and Law
PI Affiliation
Humboldt University & WZB Berlin Social Science Center
PI Affiliation
Humboldt University
PI Affiliation
Humboldt University & Tilburg Law and Economics Center
Additional Trial Information
Status
In development
Start date
2020-05-12
End date
2020-05-20
Secondary IDs
Abstract
Whether face masks are effective in slowing the spread of the COVID-19 pandemic is still a heavily debated subject. Following up on an earlier field experiment (https://www.socialscienceregistry.org/trials/5735), we seek to investigate whether a face mask policy change impacts the distance-keeping between individuals in public spaces in Berlin (Germany) where masks recently became compulsory in public transport and in stores. In this current study, we replicate the study design from an earlier study which was conducted before face masks became compulsory.
We found in the earlier study that individuals keep a significantly greater distance from experimenters wearing a mask compared to those not wearing one. In the present experiment, we expect the policy change to significantly affect the distance-keeping in response to face masks.
Registration Citation
Citation
Balleyer, Anna et al. 2020. "Face Mask Mandate and Compliance with Physical Distancing Recommendations During the COVID-19 Pandemic." AEA RCT Registry. May 13. https://doi.org/10.1257/rct.5831-1.0.
Experimental Details
Interventions
Intervention(s)
Intervention Start Date
2020-05-12
Intervention End Date
2020-05-20
Primary Outcomes
Primary Outcomes (end points)
The personal distance kept by other individuals to the experimenters.
Primary Outcomes (explanation)
The primary outcomes of the analysis will be the measured distance between the experimenter and the subject standing behind in the line and an indicator for whether or not the subject complies with the distance of 150cm.
Secondary Outcomes
Secondary Outcomes (end points)
Secondary Outcomes (explanation)
Experimental Design
Experimental Design
As this study replicates an earlier study of ours, we copied this part from the original study:
The experimenters position themselves at the end of a line to enter a business. As soon as an individual joins the line behind the experimenter, the experimenter records the distance to the next individual in line behind them. Shortly after the measurement, the experimenter leaves to rejoin the end of the line. The experimenter varies whether or not to wear an FFP2 mask according to a predefined protocol.
Experimental Design Details
As this study replicates an earlier study of ours, we copied this part from the original study: The experimenters position themselves at the end of a line (e.g. in front of the post office, see experimental protocol for details). The experimenters are adjusting themselves facing away from the line such that the person in front of them stands to their one side and the arriving subject on their opposing side; this allows the experimenters to better register incoming subjects and turn toward them to conduct the subsequent distance measurement. Then, the experimenters calibrate a measurement app on their mobile device and await the subject’s arrival to start the measurement. After the measurement is taken, the experimenters immediately record the observed variables as described below on their mobile device. Experimenters vary whether or not they wear a facial mask according to the experimental protocol. As described in the experimental protocol, experimenters measure the key dependent variable of this study using an augmented-reality measuring app. Specifically, the distance in centimeters between the experimenter and the subject next in line at the moment of joining the line and standing still will be used to assess to what extent the subject adheres to the public safety recommendation of keeping a distance of at least 150 cm. Furthermore, visibly accessible data about the subjects is recorded to be used in the analysis. Specifically, experimenters record the subjects’ gender, age, whether the subject is wearing a self-made or store-bought face mask themselves, and whether they are accompanied. If subjects are accompanied, experimenters record how many individuals are joining the subject and whether this group includes children or only adults. Furthermore, the time and date, as well as the address and store of observation, are recorded by each experimenter.
Randomization Method
As this study replicates an earlier study of ours, we copied this part from the original study:
Before each session, each of the experimenters set an even target of observations to be recorded. Half of the observations should be executed with, and the other half without a face mask on. The order is decided randomly using a fair coin by the experimenter before starting the respective session. Example: The experimenter sets the number to 20. After tossing the coin, the sessions start with 10 observations with the mask on. Then the experimenter removes the mask and performs another 10 without.

Please note that the treatment variable public policy cannot be randomized.
Randomization Unit
The treatment is randomized within experimental sessions as described in the randomization method.
Was the treatment clustered?
Yes
Experiment Characteristics
Sample size: planned number of clusters
As this study replicates an earlier study of ours, we copied this part from the original study:
The data will be collected by 5 experimenters, each collecting 60 observations. The number of clusters depends on the number of sessions onto which the experimenters will split their data collection. Details are specified in the experimental protocol.
Sample size: planned number of observations
The planned number of total observations is 300.
Sample size (or number of clusters) by treatment arms
150 with face mask, 150 without face mask
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Supporting Documents and Materials

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IRB
INSTITUTIONAL REVIEW BOARDS (IRBs)
IRB Name
IRB Approval Date
IRB Approval Number
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