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##### Social Connections and Peer Effects: An Experiment in Selective Enrollment High Schools in Peru
Last registered on November 28, 2017

#### Pre-Trial

Trial Information
General Information
Title
Social Connections and Peer Effects: An Experiment in Selective Enrollment High Schools in Peru
RCT ID
AEARCTR-0002600
Initial registration date
November 27, 2017
Last updated
November 28, 2017 10:55 AM EST
Location(s)
Region
Primary Investigator
Affiliation
Other Primary Investigator(s)
Status
On going
Start date
2016-12-10
End date
2018-03-31
Secondary IDs
Abstract
This project aims to quantify the causal effects of being exposed to peers with better cognitive and social skills. To identify these effects, I conduct an RCT in Selective Enrollment High Schools in Peru. Students were classified into four types based on admission test scores and centrality measures of social networks: (i) high-cognitive high-social, (ii) high-cognitive low-social, (iii) low-cognitive high-social, (iv) low-cognitive low-social. Conditional on the student’s type, they were randomly assigned to groups with different types of peers. These groups were used for the assignment to dormitories (in 3rd, 4th and 5th grade) and classrooms (in 3rd grade). I can use this variation to identify causal peer effects on social networks, standardized test scores, and non-cognitive skills. An important component of the latter are social skills, which will be measured by a group of psychologists through interviews and group activities. The final purpose of the project is to develop a theoretical model that uses this variation and results to identify the optimal group composition given an objective function of a policy-maker.
Registration Citation
Citation
Zarate Vasquez, Roman Andres. 2017. "Social Connections and Peer Effects: An Experiment in Selective Enrollment High Schools in Peru." AEA RCT Registry. November 28. https://doi.org/10.1257/rct.2600-1.0.
Former Citation
Zarate Vasquez, Roman Andres. 2017. "Social Connections and Peer Effects: An Experiment in Selective Enrollment High Schools in Peru." AEA RCT Registry. November 28. http://www.socialscienceregistry.org/trials/2600/history/23567.

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Experimental Details
Interventions
Intervention(s)
Students in Selective Enrollment High Schools (COAR) in Peru were assigned to groups that vary peers' baseline test scores and social skills.
Intervention Start Date
2017-04-01
Intervention End Date
2017-12-16
Primary Outcomes
Primary Outcomes (end points)
Test scores
Non-cognitive skills
Social Networks
College Outcomes
Primary Outcomes (explanation)
Secondary Outcomes
Secondary Outcomes (end points)
Secondary Outcomes (explanation)
Experimental Design
Experimental Design
Students were randomly allocated to groups that vary peer characteristics.
Experimental Design Details
The methodology of the project corresponds to a Randomized Control Trial (RCT) that varies peer characteristics in two variables: cognitive and social skills. Cognitive skills are measured by the score in the written test during the admission process. Social skills correspond to measures of centrality in social networks for 4th and 5th graders (the centrality measures were calculated using network surveys performed in November of 2016. Students were asked to list their friends, study partners, social partners and those they would like to have as roommates.) and the social-fit score (a group of psychologists who observe how do applicants interact with each other assigns an individual score for social behaviors such as cooperation, teamwork, and empathy.) for 3rd graders. In order to avoid weak variation in peers characteristics , students are categorized into four different types: (i) type HH: high cognitive and high social, (ii) type HL: high cognitive and low social, (iii) type LH: low cognitive and high social, and (iv) type LL: low cognitive and low social. Conditional on the student type, they were randomly assigned to one of ten potential groups. Each one of these groups is composed of students of one or two different types. The following chart shows the ten possible combinations that can be formed using the four types. Group 1, for example, is composed only by students of type HH, while group 3 is composed by students of types HL and LH. During the 2017 school year, 21 out of 25 schools in the COAR network followed these groups to assign students to dorms (3rd, 4th, and 5th grade) and classrooms (3rd grade). Given the composition of these groups, and that conditional on the student type they were randomly assigned to certain type of peers, the experimental design allows to identify the causal effect of being exposed to HH, HL, and LH peers relative to LL peers with the following equation: $$y_{it} = \beta_{0} + \beta_{1} HH_{it} + \beta_{2} HL_{it} + \beta_{3} LH_{it} + \gamma_{t} + \varepsilon_{it} \;, \label{eq: main}$$ where $y_{it}$ corresponds to the outcome of student $i$ categorized with type $t$; $HH_{it}$, $HL_{it}$, $LH_{it}$ correspond to dummy variables of being assigned to peers of high cognitive and high social skills, high cognitive and low social skills, and low cognitive and high social skills, respectively; $\gamma_{t}$ corresponds to type fixed effects since the likelihood of being assigned to peers of each type vary by this variable\footnote{Students of each type $t$ are twice as likely of being assigned to peers of type $t$ than of being assigned to type $\tilde{t}$ with $\tilde{t} \neq t$. }; finally, $\varepsilon_{it}$ corresponds to an error term.
Randomization Method
The randomization was done by a computer in STATA. It was stratified at the school-grade-sex level.
Randomization Unit
Individual.
Was the treatment clustered?
No
Experiment Characteristics
Sample size: planned number of clusters
There are no clusters.
Sample size: planned number of observations
For 3rd grade, the sample is composed of 2,700 students. For 4th and 5th grade, the sample is composed of 3,700 students.
Sample size (or number of clusters) by treatment arms
One-fourth of the students in each school are assigned to each type of peers.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
For students in 3rd grade there is a total of 24 school with 100 students each, plus the school in Lima that has 300 slots. This gives a total of 2,700 students in the sample for the experiment. There are 675 students exposed to each of the four types of peers. It is possible to make comparisons between these four groups by estimating an effect of 0.15 standard deviations with a power level of 0.786. For students in fourth and fifth grade, there is a total of 3,764 students enrolled with measures of cognitive and social skills prior to the randomization of the experiment. This implies that each group exposed to each type of classmates consists of 941 students. This allows comparisons between the four groups by estimating an effect of 0.13 standard deviations with a power level of 0.804.
IRB
INSTITUTIONAL REVIEW BOARDS (IRBs)
IRB Name
Massachusetts Institute of Technology
IRB Approval Date
2017-03-09
IRB Approval Number
1702862092
##### Post-Trial
Post Trial Information
Study Withdrawal
Intervention
Is the intervention completed?
No
Is data collection complete?
Data Publication
Data Publication
Is public data available?
No
Program Files
Program Files
Reports, Papers & Other Materials
Relevant Paper(s)
REPORTS & OTHER MATERIALS