Balance Statistics for MatchIt Objects
Generates balance statistics for matchit
objects from MatchIt.
## S3 method for class 'matchit' bal.tab(x, method, stats, int = FALSE, poly = 1, distance = NULL, addl = NULL, data = 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, ...)
x |
a |
method |
a character vector containing the method of adjustment. Ignored unless subclassification was used in the original call to |
stats |
|
int |
|
poly |
|
distance |
an optional formula or data frame containing distance values (e.g., propensity scores) or a character vector containing their names. If a formula or variable names are specified, |
addl |
an optional formula or data frame containing additional covariates for which to present balance or a character vector containing their names. If a formula or variable names are specified, |
data |
an optional data frame containing variables that might be named in arguments to |
continuous |
whether mean differences for continuous variables should be standardized ( |
binary |
whether mean differences for binary variables (i.e., difference in proportion) should be standardized ( |
s.d.denom |
|
thresholds |
a named vector of balance thresholds, where the name corresponds to the statistic (i.e., in |
weights |
a named list containing additional weights on which to assess balance. Each entry can be a vector of weights, the name of a variable in |
cluster |
either a vector containing cluster membership for each unit or a string containing the name of the cluster membership variable in |
imp |
either a vector containing imputation indices for each unit or a string containing the name of the imputation index variable in |
pairwise |
whether balance should be computed between the treatment groups or for each treatment against all groups combined. See |
s.weights |
optional; either a vector containing sampling weights for each unit or a string containing the name of the sampling weight variable in |
abs |
|
subset |
a |
quick |
|
... |
further arguments to control display of output. See display options for details. |
bal.tab.matchit()
generates a list of balance summaries for the matchit
object given, and functions similarly to MatchIt::summary.matchit()
. bal.tab()
behaves differently depending on whether subclasses are used in conditioning or not. If they are used, bal.tab()
creates balance statistics for each subclass and for the sample in aggregate; see bal.tab.subclass
for more information.
The threshold
argument controls whether extra columns should be inserted into the Balance table describing whether the balance statistics in question exceeded or were within the threshold. Including these thresholds also creates summary tables tallying the number of variables that exceeded and were within the threshold and displaying the variables with the greatest imbalance on that balance measure. When subclassification is used, the extra threshold columns are placed within the balance tables for each subclass as well as in the aggregate balance table, and the summary tables display balance for each subclass.
If subclassification is used and method
is set to "subclassification"
, an object of class "bal.tab.subclass"
containing balance summaries within and across subclasses. See bal.tab.subclass
for details.
If matching is used and clusters are not specified, an object of class "bal.tab"
containing balance summaries for the matchit
object. See bal.tab()
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.
Noah Greifer
bal.tab()
for details of calculations.
library(MatchIt); data("lalonde", package = "cobalt") ## Nearest Neighbor matching m.out1 <- matchit(treat ~ age + educ + race + married + nodegree + re74 + re75, data = lalonde, method = "nearest") bal.tab(m.out1, un = TRUE, m.threshold = .1, v.threshold = 2) ## Subclassification m.out2 <- matchit(treat ~ age + educ + race + married + nodegree + re74 + re75, data = lalonde, method = "subclass") bal.tab(m.out2, disp.subclass = TRUE)
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