The value of friends: Experimental evidence on secondary schooling decisions

Last registered on March 21, 2023


Trial Information

General Information

The value of friends: Experimental evidence on secondary schooling decisions
Initial registration date
March 20, 2023

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
March 21, 2023, 4:58 PM EDT

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



Primary Investigator

Nova School of Business and Economics

Other Primary Investigator(s)

PI Affiliation
PI Affiliation
PI Affiliation
PI Affiliation

Additional Trial Information

In development
Start date
End date
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
In many countries, students must decide at a young age on a course of study which will shape not only their experience in school, but in the labor market, and beyond. How much value do these students put on sharing a course of study with their friends? We conduct a randomized experiment among 9th grade students in Portugal, who will decide within a few months which course to pursue in secondary school. We ask students who their best friend in their class is, then elicit students' preferred (and second-preferred) course, as well as their beliefs about their best friend's course. We also elicit their beliefs over the returns to these courses. We then present a series of hypothetical scenarios, in which we vary the potential returns to different courses and elicit course preferences in each scenario. We randomly vary which students see these hypothetical scenarios framed as an opportunity to be in a course with their best friend. By measuring the differences in the point at which students switch courses, we can recover a monetary value students place on being in their friend's course in secondary school.
External Link(s)

Registration Citation

Balcão Reis, Ana et al. 2023. "The value of friends: Experimental evidence on secondary schooling decisions." AEA RCT Registry. March 21.
Experimental Details


Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
Student valuation of their first course choice
Primary Outcomes (explanation)
- Student valuation of first course choice: see "intervention" section.
- Switching: binary. Does a student switch their course choice for any hypothetical value presented for the returns to the course?

Secondary Outcomes

Secondary Outcomes (end points)
Closeness to friends
Course choice
Secondary Outcomes (explanation)
Closeness to friends: we ask students how close they feel to their friends using a diagram, and ask how likely they think it is they will continue to be friends 10 and 20 years from now.
Course choice: student's eventual 10th-grade course choice (self report, and matched from admin data)

Experimental Design

Experimental Design
We randomize the framing of the hypothetical scenarios at the individual level, to include or not a mention of whether each course option would or would not be with the student's best friend.
Experimental Design Details
Randomization Method
Individual randomizaion performed by Qualtrics survey software
Randomization Unit
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
2000 individuals
Sample size: planned number of observations
2000 individuals
Sample size (or number of clusters) by treatment arms
1000 individuals control, 1000 individuals friend framing
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)

Institutional Review Boards (IRBs)

IRB Name
Ethics Committee of Nova School of Business and Economics
IRB Approval Date
IRB Approval Number


Post Trial Information

Study Withdrawal

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Is the intervention completed?
Data Collection Complete
Data Publication

Data Publication

Is public data available?

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials