Compute School Distance from a Student Match

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Description

Defines a distance between two schools whose students have been matched based on the size of the resulting matched sample and on the student-level covariate balance.

Usage

1
match2distance(matchFrame, treatFrame, ctrlFrame, student.vars, treatment, largeval)

Arguments

matchFrame

dataframe containing all matched students.

treatFrame

dataframe containing all students from the treated school.

ctrlFrame

dataframe containing all students from the control school.

student.vars

names of variables on which to evaluate balance in the matched sample. Must be present in the column names of each of matchFrame, treatFrame and ctrlFrame.

treatment

name of the treatment variable. Must be present in the column names of each of matchFrame, treatFrame and ctrlFrame.

largeval

a large penalty value to be added to the distance for each student-level imbalance.

Details

The distance is computed by (1) subtracting the harmonic mean of the treated and control counts in the matched sample from largeval (2) adding largeval for each covariate among studentvars that has an absolute standardized difference exceeding 0.2. This encourages the school match to choose larger schools with better balance.

Value

a numeric distance.

Author(s)

Luke Keele, Penn State University, ljk20@psu.edu

Sam Pimentel, University of Pennsylvania, spi@wharton.upenn.edu