Balance Statistics for cem Objects

Generates balance statistics for cem.match objects from cem.

# S3 method for cem.match
bal.tab(x, 
        data,
        stats,
        int = FALSE,
        poly = 1,
        distance = NULL,
        addl = NULL,
        continuous,
        binary,
        s.d.denom,
        thresholds = NULL,
        weights = NULL,
        cluster = NULL,
        imp = NULL,
        pairwise = TRUE,
        s.weights = NULL,
        abs = FALSE,
        subset = NULL,
        quick = TRUE,
        ...)

Arguments

x

a cem.match or cem.match.list object; the output of a call to cem::cem().

data

a data frame containing variables named in other arguments. An argument to data is required. It must be the same data used in the call to cem() or a mids object from which the data supplied to datalist in the cem() call originated.

stats, int, poly, distance, addl, continuous, binary, thresholds, weights, cluster, imp, pairwise, s.weights, abs, subset, quick, ...

see bal.tab() for details.

See below for a special note on the s.d.denom argument.

The following argument has a special note when used with cem.match or cem.match.list objects:

s.d.denom

the default is "treated", where the treated group corresponds to the baseline.group in the call to cem().

Details

bal.tab.cem.match() generates a list of balance summaries for the cem.match object given, and functions similarly to cem::imbalance().

Value

If clusters and imputations are not specified, an object of class "bal.tab" containing balance summaries for the cem.match object. See bal.tab() for details.

If imputations are specified, an object of class "bal.tab.imp" containing balance summaries for each imputation and a summary of balance across imputations. See bal.tab.imp for details.

If cem() is used with multi-category treatments, an object of class "bal.tab.multi" containing balance summaries for each pairwise treatment comparison. See bal.tab.multi for details.

If clusters are specified, an object of class "bal.tab.cluster" containing balance summaries within each cluster and a summary of balance across clusters. See bal.tab.cluster for details.

Author

Noah Greifer

See also

bal.tab() for details of calculations.

Examples

library(cem); data("lalonde", package = "cobalt")
#> Loading required package: tcltk
#> 
#> How to use CEM? Type vignette("cem")
#> 
#> Attaching package: ‘cem’
#> The following object is masked from ‘package:optmatch’:
#> 
#>     pair

## Coarsened exact matching
cem.out <- cem("treat", data = lalonde, drop = "re78")
#> 
#> Using 'treat'='1' as baseline group

bal.tab(cem.out, data = lalonde, un = TRUE, 
        stats = c("m", "k"))
#> Balance Measures
#>                Type Diff.Un  KS.Un Diff.Adj KS.Adj
#> age         Contin. -0.3094 0.1577   0.0512 0.1581
#> educ        Contin.  0.0550 0.1114  -0.0441 0.0445
#> race_black   Binary  0.6404 0.6404   0.0000 0.0000
#> race_hispan  Binary -0.0827 0.0827   0.0000 0.0000
#> race_white   Binary -0.5577 0.5577   0.0000 0.0000
#> married      Binary -0.3236 0.3236   0.0000 0.0000
#> nodegree     Binary  0.1114 0.1114   0.0000 0.0000
#> re74        Contin. -0.7211 0.4470  -0.0341 0.2418
#> re75        Contin. -0.2903 0.2876  -0.0528 0.1162
#> 
#> Sample sizes
#>                      Control Treated
#> All                   429.       185
#> Matched (ESS)          36.29      68
#> Matched (Unweighted)   78.        68
#> Unmatched             351.       117