matching {arm} | R Documentation |
Function for processing matching with propensity score
matching(z, score)
z |
vector of indicators for treatment or control. |
score |
vector of the propensity scores in the same order as z. |
Function for matching each treatment unit in turn the control unit (not previously chosen) with the closest propensity score
The function returns a vector of indices that the corresponding unit is matched to. 0 means matched to nothing.
Jeniffer Hill jh1030@columbia.edu; Yu-Sung Su ys463@columbia.edu
Andrew Gelman and Jennifer Hill, Data Analysis Using Regression and Multilevel/Hierarchical Models, Cambridge University Press, 2006.
# matching first data(lalonde) attach(lalonde) fit <- glm(treat ~ re74 + re75 + age + factor(educ) + black + hisp + married + nodegr + u74 + u75, family=binomial(link="logit")) pscores <- predict(fit, type="link") matches <- matching(z=lalonde$treat, score=pscores) matched <- lalonde[matches$matched,] # make the plot par(mar=c(0,6,4,2),mgp=c(2,0.25,0),tcl=-0.2) balanceplot(lalonde, matched, fit, xlim=c(-0.3,0.2))