Project info
Work package
- Work
Sustainability threat
- Spillovers
Challenge
- Reconfiguring-roles-and-relationships
Study info
Description of Study
People become friends with one another primarily due to things they have in common, like shared demographic characteristics or shared interests. But on what similarities are people becoming friends at different stages of knowing one another? To study this, we use a longitudinal dataset that followed a cohort of students of one study programme at a Swiss technical university. We model how demographic traits of nationality and gender, and less observable interest-related traits of being social, a partygoer, a smart and hard-working student, contribute to friendships. Using Stochastic Actor-Oriented Models, we find a baseline level of both demographic and interest-related friendship homophily, indicating that there are differing reasons behind friendships. We also find that homophily based on demographic traits diminishes over time when students get to know those in their study cohort better. This suggest that homophily on observable traits is mainly relevant when people first meet but becomes less important over time.
Study research question
Collection provenance
- External data
Collection methods
- Questionaire
Personal data
Yes
External Source
Source description
Subset of the data focusing on friendships, demographic characteristics and perceptions of other students (e.g. if they're clever, party going, etc.), over 5 waves in a 1 year period - during the first year of their university studies
File formats
- .csv
Data types
- Structured
Languages
- English
Coverage start
Coverage end
19/09/2017
20/05/2018
Spatial coverage
ETH Zurich, Zurich, Switzerland
Collection period start
—
Collection period end
—
Variables
Unit
Unit description
Sample size
Sampling method
Individuals
Students
660
Questionairres
Hypothesis
Theory
H1: Similarity on surface-level (demographic) characteristics drives friendship formation.
Social Identity Theory/ Homophily
H2: Similarity in deep-level characteristics (non-demographic) drives friendship formation.
Social Identity Theory/ Homophily
H3a: Over time, shared surface-level characteristics become weaker predictors of friendship formation.
Identity Salience/ Ethnic by-products
H3b: Over time, shared deep-level characteristics become stronger predictors of friendship formation.
Identity Salience/ Ethnic by-products
H4: Over time, the network will have lower levels of demographic friendship segregation.
Homophily/ Segregation
Variable type
Variable name
Variable description
Dependent variable
Friendship
Whether or not two students are friends in the given wave of analysis.
Independent variable
Sex
The sex of the individual respondent
Independent variable
International Student Status
Whether or not the student is Swiss (local) or not (international)
Independent variable
Party Goer (Indegree)
How many nominations from fellow students perceiving the individual as a party goer.
Independent variable
Clever
How many nominations from fellow students perceiving the individual as clever.
Independent variable
Hard working
How many nominations from fellow students perceiving the individual as a hard worker.
Independent variable
Social
How many nominations from fellow students perceiving the individual as a social person.
Control variable
Known before
Whether or not a pair of students knew each other before entering university.
Control variable
Live With
Whether or not a pair of students live with one another.
Discipline-specific operationalizations
Conflict of interest
Data packages
Publications
Documents
Filename
Description
Date
Ethics
Ethical assessment
Yes
Ethical committee
ethics board of ETH Zürich (approval 2016-N-27 and 2017-N-42)