Peer Pressure: Experimental Evidence from Restroom Behavior

Last registered on May 02, 2017


Trial Information

General Information

Peer Pressure: Experimental Evidence from Restroom Behavior
Initial registration date
May 02, 2017
Last updated
May 02, 2017, 1:36 PM EDT



Primary Investigator

Universidad de San Andres

Other Primary Investigator(s)

PI Affiliation
Universidad de San Andrés

Additional Trial Information

Start date
End date
Secondary IDs
This study provides experimental evidence on the effect of peer pressure on individual behavior by seeing being exposed to an observer increases the probability of handwashing. The results indicate that being exposed to an observer does increase this probability by 13 percentage points and the probability of urinal flushing by 15 percentage points.
External Link(s)

Registration Citation

, and Martin Rossi. 2017. "Peer Pressure: Experimental Evidence from Restroom Behavior." AEA RCT Registry. May 02.
Former Citation
, , Martin Rossi and Martin Rossi. 2017. "Peer Pressure: Experimental Evidence from Restroom Behavior." AEA RCT Registry. May 02.
Experimental Details


The purpose of the intervention is to study whether social pressure influences public restroom behavior in male adults.
Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
handwashing, urinal flushing
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
The experiment was performed in male restrooms at Universidad de San Andrés in order to assess the effect of social pressure on two variables of interest: handwashing and urinal flushing. The experiment itself was conducted in three shifts: 1) a morning shift from 10 am to 12 pm, 2) mid-day shift from 12-2pm and 3) afternoon shift from 2-4pm. Six males acted out as the evaluators. They would each enter the restroom 8 seconds after the participant and place himself at another urinal. The observer would then act as another user of the restroom, without flushing the urinal or washing his hands. The evaluator would then note if the participant would flush the urinal or wash his hands after using the urinal. For the control group, the evaluator waited outside and listened if the participant flushed the urinal and/or washed his hands.

The results indicate that 66.3% of people wash their hands in public restrooms when no one else is present and this proportion increases by 12.5 percentage points if someone else is present, thereby suggesting that male handwashing in public restrooms is influenced by peer pressure. Similarly, 55.7% of people flush the urinal when no one is present and this raises by 14.9 percentage points if someone is present so that urinal flushing in public restrooms is influenced by peer pressure.
Experimental Design Details
Randomization Method
Randomization procedure called BCD which sequentially assigns the participants to control or treated group
Randomization Unit
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
Not specified
Sample size: planned number of observations
Not specified
Sample size (or number of clusters) by treatment arms
Not specified
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)

Institutional Review Boards (IRBs)

IRB Name
IRB Approval Date
IRB Approval Number


Post Trial Information

Study Withdrawal

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Is the intervention completed?
Intervention Completion Date
January 01, 2017, 12:00 +00:00
Data Collection Complete
Data Collection Completion Date
January 01, 2017, 12:00 +00:00
Final Sample Size: Number of Clusters (Unit of Randomization)
Not specified
Was attrition correlated with treatment status?
Final Sample Size: Total Number of Observations
Not specified
Final Sample Size (or Number of Clusters) by Treatment Arms
Not specified
Data Publication

Data Publication

Is public data available?

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials