6 Bootstrapping

library(PSAboot)

boot.matching.1to3 <- function(Tr, Y, X, X.trans, formu, ...) {
    return(boot.matching(Tr=Tr, Y=Y, X=X, X.trans=X.trans, formu=formu, M=3, ...))
}


boot_out <- PSAboot(Tr = lalonde$treat == 1, 
                    Y = lalonde$re78, 
                    X = lalonde[,all.vars(lalonde.formu)[-1]], 
                    seed = 2112,
                    methods=c('Stratification' = boot.strata,
                              'ctree' = boot.ctree,
                              'rpart' = boot.rpart,
                              'Matching' = boot.matching,
                              'Matching-1-to-3' = boot.matching.1to3,
                              'MatchIt' = boot.matchit) )

summary(boot_out)

plot(boot_out)

Figure 6.1: Mean difference across all bootstrap samples by method

boxplot(boot_out)

matrixplot(boot_out)

boot_balance <- balance(boot_out)
boot_balance

## Unadjusted balance: 1.48309081605193

## 0.04
## 0.08
## 0.05
## 0.06
## 0.01
## 0.06
## 0.04
##  NA
## 0.07
## 0.07
## 0.05
## 0.08

plot(boot_balance)

boxplot(boot_balance) + geom_hline(yintercept=.1, color='red')

Details are available within the returned object

boot_balance$unadjusted

## 3.51
## 5.46
## 1.12
## 1.16
## 0.66
## 0.89
## 0.39
## 0.44
## 0.72
## 0.49

boot_balance$complete

## 0.04
## 0.00
## 0.00
## 0.01
## 0.00
## 0.16
## 0.03
## 0.16
## 0.05
## 0.04
## 0.02
## 0.06
## 0.09
## 0.15
## 0.14
## 0.04
## 0.01
## 0.02
## 0.04
## 0.05
## 0.08
## 0.04
## 0.00
## 0.09
## 0.02
## 0.08
## 0.10
## 0.09
## 0.01
## 0.02
## 0.03
## 0.08
## 0.02
## 0.09
## 0.02
## 0.07
## 0.00
## 0.09
## 0.05
## 0.06
## 0.00
## 0.00
## 0.03
## 0.09
## 0.01
## 0.07
## 0.01
## 0.04
## 0.06
## 0.06
## 0.06
## 0.02
## 0.05
## 0.08
## 0.03
## 0.03
## 0.01
## 0.10
## 0.00
## 0.05

boot_balance$pooled |> head()

## 0.02
## 0.03
## 0.04
## 0.03
## 0.04
## 0.05
## 0.07
## 0.09
## 0.12
##  NA
## 0.06
## 0.12
## 0.05
## 0.09
## 0.08
## 0.11
## 0.08
## 0.07
## 0.06
## 0.07
## 0.03
## 0.07
## 0.05
## 0.06
## 0.04
## 0.03
## 0.03
## 0.08
## 0.03
## 0.05
## 0.08
## 0.10
## 0.09
## 0.07
## 0.10
## 0.10