Gender Differences in Collaborative Networks

Last registered on October 04, 2023
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Pre-Trial

Trial Information

General Information

Title
Gender Differences in Collaborative Networks
RCT ID
AEARCTR-0011433
Initial registration date
May 16, 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
October 04, 2023, 5:10 PM EDT

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

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Primary Investigator

Name
Friederike Mengel
Affiliation
Uni Essex
Contact Primary Investigator

Other Primary Investigator(s)

PI Name
Valentina Ciriotto
PI Affiliation
University of Siena

Additional Trial Information

Status
In development
Start date
2023-05-16
End date
2024-05-14
Keywords
Behavior, Gender
Additional Keywords
Networks
JEL code(s)
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
We study gender differences in collaborative networks in a lab experiment. Participants can form links with others and then engage in a joint project with their network neighbours. While there is some prior research on gender differences in networking, our setting exploits a unique experimental design to study not only the number of links but also the strength of ties and the productivity of each link.
External Link(s)

Registration Citation

Citation
Ciriotto, Valentina and Friederike Mengel. 2023. "Gender Differences in Collaborative Networks." AEA RCT Registry. October 04. https://doi.org/10.1257/rct.11433-1.0
Sponsors & Partners
Experimental Details

Interventions

Intervention(s)
Intervention Start Date
2023-05-17
Intervention End Date
2024-03-11

Primary Outcomes

Primary Outcomes (end points)
Networks:
• The number of unilateral links
• The number of bilateral links
• The strength of ties
Productivity:
• Average productivity of (bilateral) links.
• Range of productivity of (bilateral) links.
Primary Outcomes (explanation)
We are interested in gender differences both in outcomes relating to the structure of networks as well as to the productivity of each link.
Networks:
• The number of unilateral links is defined as the average number of (unilateral) links a participant forms per round. A unilateral link is a linking attempt (whether successful or not).
• The number of bilateral links is defined as the average number of (bilateral) links a participant forms per round. A bilateral link is a successfully established link between two participants.
Hence for each participant i unilateral links is a superset of bilateral links.
To compute the average strength of a participant’s ties we first define the intensity of each of i’s links ij as the share of all rounds in which ij=1, i.e. in which the bilateral link ij was established.
• The strength of ties is the ratio of the weighted sum of i’s links where the weight of each link is given by its intensity over the (unweighted) sum of all links.

Productivity:
• Average productivity of (bilateral) links.
• Range of productivity of (bilateral) links (the difference between the most and least productive match).

Secondary Outcomes

Secondary Outcomes (end points)
Networks
• Homophily in bilateral links.
• Persistence of bilateral links
Secondary Outcomes (explanation)
Homophily will be measured using the inbreeding index (see e.g. Currarini et al 2009, Mengel, 2020).
Persistence of bilateral link will be measures by the conditional probability Pr(ij^t=1|ij^(t-1)=1).

Experimental Design

Experimental Design
In our experiment participants are randomly assigned in groups of six participants. Within each group they can form links via bilateral agreement to jointly work on a task. Participants can hold multiple links (collaborations) simultaneously in each round but there is an opportunity cost as all these collaborations have to be conducted under a fixed time budget.
Experimental Design Details
Not available
Randomization Method
computer
Randomization Unit
experimental session
Was the treatment clustered?
Yes

Experiment Characteristics

Sample size: planned number of clusters
75 groups
Sample size: planned number of observations
450 individuals
Sample size (or number of clusters) by treatment arms
150 individual or 25 clusters per treatment.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
0.22 Power Analysis: Our main specification will regress the outcome in question (see above) on the gender of participant i controlling for age, nationality, education, round and session fixed effects. Standard errors will be clustered at the group level. We will conduct all regressions using the entire sample as well as the subsample of the last 5 periods only where we observe more “mature” behaviour in this environment. As there are no prior studies with effect sizes on which to base our choice of sample size we proceeded as follows. We conducted sessions with 60 participants in total of the treatment with heterogeneous task value. In these sessions we detected an effect size of around -0.22 (coefficient on the female dummy) for our main specification and our first outcome (average number of unilateral links). We calculate the sample size needed to detect this effect size using a simple t-test (80% power at significance level of 0.05) and then augment it to give us enough power for our other main outcomes as well as to do subsample analysis. Taken together these considerations lead us to adopt a sample size of 150 participants per treatment.
Supporting Documents and Materials
IRB

Institutional Review Boards (IRBs)

IRB Name
University of Essex Social Sciences Ethics Subcommittee
IRB Approval Date
2023-03-29
IRB Approval Number
ETH2223-1041
Analysis Plan