bal.table: Compute balance table

In twang: Toolkit for Weighting and Analysis of Nonequivalent Groups

Description

Extract the balance table from ps, dx.wts, and mnps objects

Usage

bal.table(x, digits = 3, collapse.to = c("pair","covariate","stop.method")[1], 
	subset.var = NULL, subset.treat = NULL, subset.stop.method = NULL, es.cutoff = 0, 
	ks.cutoff = 0, p.cutoff = 1, ks.p.cutoff = 1, timePeriods = NULL, ...)

Arguments

x	a ps or dx.wts object
digits	The number of digits that the numerical entries should be rounded to.
collapse.to	For mnps ATE objects, the comparisons can be given for all pairs (default), summarized by pre-treatment covariate and stop.method, or as a single summary for each stop.method.
subset.var	Eliminate all but a specified subset of covariates.
subset.treat	Subset to either all pairs that include a specified treatment or a single pair of treatments.
subset.stop.method	Subset to a subset of stop.method\'s used to fit the ps object.
es.cutoff	Subsets to comparisons with absolute ES values bigger than es.cutoff.
ks.cutoff	Subsets to comparisons with KS values bigger than ks.cutoff.
p.cutoff	Subsets to comparisons with t- or chi-squared p-values no bigger than p.cutoff.
ks.p.cutoff	Subsets to comparisons with KS p-values no bigger than ks.p.cutoff.
timePeriods	Used to subset times for iptw fits.
...	Additional arugments.

Details

bal.table is a generic function for extracting balance tables from ps and dx.wts objects. These objects usually have several sets of candidate weights, one for an unweighted analysis and perhaps several stop.methods. bal.table will return a table for each set of weights combined into a list. Each list component will be named as given in the x, usually the name of the stop.method. The balance table labeled “unw” indicates the unweighted analysis.

Value

Returns a data frame containing the balance information.

tx.mn	The mean of the treatment group
tx.sd	The standard deviation of the treatment group
ct.mn	The mean of the control group
ct.sd	The standard deviation of the control group
std.eff.sz	The standardized effect size, (tx.mn-ct.mn)/tx.sd. If tx.sd is small or 0, the standardized effect size can be large or INF. Therefore standardized effect sizes greater than 500 are set to NA
stat	the t-statistic for numeric variables and the chi-square statistic for continuous variables
p	the p-value for the test associated with stat
ks	the KS statistic
ks.pval	the KS p-value computed using the analytic approximation, which does not necessarily work well with a lot of ties

See Also

The example for ps contains an example of the use of bal.table

twang documentation built on May 2, 2019, 6:53 p.m.