dx.wts {twang} | R Documentation |
dx.wts
takes a ps
object or a set of propensity scores and
computes diagnostics assessing covariates balance.
dx.wts(x, data, vars=NULL, treat.var, x.as.weights=TRUE, sampw=NULL, perm.test.iters=0, plots=TRUE, title)
x |
a data frame, matrix, or vector of propensity score weights or a ps
object. x can also be a data frame, matrix, or vector of
propensity scores if x.as.weights=FALSE |
data |
a data frame |
vars |
a vector of character strings naming variables in data on
which to assess balance |
treat.var |
a character string indicating which variable in data
contains the 0/1 treatment group indicator |
x.as.weights |
TRUE or FALSE indicating whether x
specifies propensity score weights or propensity scores.
Ignored if x is a ps object |
sampw |
optional sampling weights. If x is a ps object then the
sampling weights should have been passed to ps and
not specified here. dx.wts will issue a warning if
x is a ps object and sampw is also specified |
perm.test.iters |
an non-negative integer giving the number of iterations
of the permutation test for the KS statistic. If perm.test.iters=0
then the function returns an analytic approximation to the p-value. This
argument is ignored is x is a ps object. Setting
perm.test.iters=200 will yield precision to within 3% if the true
p-value is 0.05. Use perm.test.iters=500 to be within 2% |
plots |
if plots=TRUE then dx.wts will call
diag.plot generating diagnostic plots |
title |
a short text title, it will be used in plots and saved files. By default this is set to the current date and time |
Creates a balance table that compares unweighted and weighted means and standard deviations, computes effect sizes, and KS statistics to assess the ability of the propensity scores to balance the treatment and control groups.
Returns a list containing
treat |
the vector of 0/1 treatment assignment indicators |
desc |
a nested list containing detailed diagnostic information on the weights. This includes the number of treatment and control subjects, the effective sample size, the largest KS statistic, the average absolute effect size, and the complete balance table |
summary.tab |
a data frame showing balance information |
ps |
the given propensity scores |
w |
the given weights |
datestamp |
the date and time of the call to dx.wts |
parameters |
the parameters used when calling dx.wts |
alerts |
text containing any warnings accumulated during the estimation |
The example for ps
contains an example of the
use of dx.wts
, diag.plot