Understanding Loneliness

Last registered on July 01, 2025

Pre-Trial

Trial Information

General Information

Title
Understanding Loneliness
RCT ID
AEARCTR-0004677
Initial registration date
September 07, 2019

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
September 09, 2019, 6:27 PM EDT

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

Last updated
July 01, 2025, 1:16 PM EDT

Last updated is the most recent time when changes to the trial's registration were published.

Locations

Region

Primary Investigator

Affiliation
Harvard University

Other Primary Investigator(s)

PI Affiliation
Harvard University

Additional Trial Information

Status
Completed
Start date
2019-09-10
End date
2020-09-30
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
See pre-analysis plan
External Link(s)

Registration Citation

Citation
Anders, Jenna and Amanda Pallais. 2025. "Understanding Loneliness." AEA RCT Registry. July 01. https://doi.org/10.1257/rct.4677-2.0
Experimental Details

Interventions

Intervention(s)
Intervention (Hidden)
The project is motivated by the question of how so many people can be lonely. Why don’t individuals who are lonely find each other? In many other settings, we expect that market participants who would benefit from trade will find each other.

We propose a search model which motivates the experiment. Individuals are searching for friends who will be a good (as opposed to bad) match for them. (Most potential friends are a bad match.) The only way to learn about match quality is through interacting. Individuals are paired with a friend and can choose to interact (thereby learning about match quality) or take their outside option. Individuals will only choose to interact with a potential match if their perceived probability that the match is good is sufficiently high. Since we expect that the baseline probability that a match is good is low, while outside options are high, this requires at least a few positive signals. This leads to a Catch 22: an individual will not meet up with a potential friend until she receives positive signals about the match, but she can’t receive positive signals without meeting up. However, once a pair believes a match is sufficiently likely to be good, it will continue to interact; these matches will be largely self-sustaining.

Individuals may also have passive interactions with potential friends: these are interactions that occur while individuals engage in activities they would otherwise do. The key is that individuals don’t have to pay an opportunity cost to acquire these passive signals. Passive interactions are the only type of interaction people will have with potential friends they don't know well (since their probability of being a match is sufficiently low). Passive interactions are required to form friendships in this model.

The experiment is designed to put Ph.D. students in groups and then induce students to have four passive interactions with their groups. The idea is that this may push some pairs over the threshold to interact outside of the intervention.

Specifically, interested Ph.D. students will sign up for a four-week trivia competition in teams of six or as individuals or small groups. If more teams sign up than we can accommodate, we will randomize which teams get to participate. Treated teams will be signed up to participate in a four-week trivia competition. They will be invited to come to trivia night every Tuesday night for four weeks with their same team. These trivia nights are modeled after standard bar trivia, but intended to be more accessible and appealing to Ph.D. students than traditional bar trivia. They include free food, prizes, and an opportunity to mingle with other teams. Teams randomized into the control group will not be able to participate in the trivia competition.
Intervention Start Date
2019-10-01
Intervention End Date
2019-10-22

Primary Outcomes

Primary Outcomes (end points)
See pre-analysis plan.
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
See below.
Experimental Design Details
Interested Ph.D. students will sign up for a four-week trivia competition. They will hear about the trivia competition through a variety of methods (e.g., facebook, emails, word of mouth). Students will be allowed to sign up in (1) pre-formed teams of six or (2) in small groups or individually to be placed in teams of six. When students sign up for the trivia competition, they will consent to be in the study and be asked to complete a baseline survey. After students sign up, we will combine individuals and small groups into teams of six (depending on the number of signups, we may not be able to form teams of exactly six). We will eliminate teams that are mostly non-Ph.D. students (e.g., undergrads or masters students if they mistakenly sign up) or economics Ph.D. students. (Economics Ph.D. students were invited to participate in a pilot.)

Then, we will randomize which teams get in. We will stratify based on whether the teams are pre-formed teams of six or teams that we created from individuals and small groups who signed up. Treated teams will be invited to attend the trivia competition, while control teams will not. We view the trivia competition as inducing teams to spend time with each other on four distinct social occasions. (Of course, students are not forced to attend the trivia if they get in and can choose to come on some nights and not others.)

Students in both the treatment and control groups will be asked to complete 3 follow-up surveys that will be distributed via email and text. The first will be during the trivia competition, the second will be roughly a month after the end of the trivia competition, and the final survey will be at the beginning of the spring semester.

These surveys as well as the baseline survey will ask information about individuals’ relationship with their teammates as well as their overall social activities, loneliness, and satisfaction with their social life. Students will get $15 from Amazon.com as a reward for taking each survey. If they complete all four, they will get an additional $10 from Amazon.com.
Randomization Method
See pre-analysis plan.
Randomization Unit
See pre-analysis plan.
Was the treatment clustered?
Yes

Experiment Characteristics

Sample size: planned number of clusters
See pre-analysis plan.
Sample size: planned number of observations
See pre-analysis plan.
Sample size (or number of clusters) by treatment arms
See pre-analysis plan.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
IRB

Institutional Review Boards (IRBs)

IRB Name
Harvard University-Area Committee on the Use of Human Subjects
IRB Approval Date
2019-08-07
IRB Approval Number
IRB19-1077
Analysis Plan

Analysis Plan Documents

Understanding Loneliness

MD5: f782adfad3c4d8398982a2b189dac0ac

SHA1: b507da419c1bf1021b0562683caa0a4b1c13993d

Uploaded At: September 09, 2019

Post-Trial

Post Trial Information

Study Withdrawal

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Intervention

Is the intervention completed?
Yes
Intervention Completion Date
October 22, 2019, 12:00 +00:00
Data Collection Complete
Yes
Data Collection Completion Date
March 11, 2020, 12:00 +00:00
Final Sample Size: Number of Clusters (Unit of Randomization)
25 treated teams, 25 control teams
Was attrition correlated with treatment status?
Yes
Final Sample Size: Total Number of Observations
Individuals: 129 treated individuals, 128 control individuals
Pairs who signed up together: 285 treated pairs, 279 control pairs
Matched pairs: 48 treated pairs, 44 control pairs
Final Sample Size (or Number of Clusters) by Treatment Arms
25 treated teams, 25 control teams
Data Publication

Data Publication

Is public data available?
No

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials