balanceUV {Matching} | R Documentation |
This function provides a number of univariate balance metrics.
Generally, users should call MatchBalance
and not this function
directly.
balanceUV(Tr, Co, weights = rep(1, length(Co)), exact = FALSE, ks=FALSE, nboots = 1000, paired=TRUE, match=FALSE, weights.Tr=rep(1,length(Tr)), weights.Co=rep(1,length(Co)))
Tr |
A vector containing the treatment observations. |
Co |
A vector containing the control observations. |
weights |
A vector containing the observation specific weights. Only use this option when the treatment and control observations are paired (as they are after matching). |
exact |
A logical flag indicating if the exact Wilcoxon test
should be used instead of the test with a correction. See
wilcox.test for details. |
ks |
A logical flag for if the univariate bootstrap
Kolmogorov-Smirnov (KS) test should be calculated. If the ks option
is set to true, the univariate KS test is calculated for all
non-dichotomous variables. The bootstrap KS test is consistent even
for non-continuous variables. See ks.boot for more
details. |
nboots |
The number of bootstrap samples to be run for the
ks test. If zero, no bootstraps are done. Bootstrapping is
highly recommended because the bootstrapped Kolmogorov-Smirnov test
only provides correct coverage even for non-continuous covariates. At
least 500 nboots (preferably 1000) are
recommended for publication quality p-values. |
paired |
A flag for if the paired t.test should be used. |
match |
A flag for if the Tr and Co objects are the result
of a call to Match . |
weights.Tr |
A vector of weights for the treated observations. |
weights.Co |
A vector of weights for the control observations. |
sdiff |
This is the standardized difference between the treated and control units. That is, the mean difference between treatment and control units divided by the pooled standard deviation. |
mean.Tr |
The mean of the treatment group. |
mean.Co |
The mean of the control group. |
var.Tr |
The variance of the treatment group. |
var.Co |
The variance of the control group. |
p.value |
The p-value from the two-sided weighted t.test . |
var.ratio |
var.Tr/var.Co. |
ks |
The object returned by ks.boot . |
tt |
The object returned by two-sided weighted
t.test . |
qqsummary |
The return object from a call to
qqstats with standardization. |
qqsummary.raw |
The return object from a call to
qqstats without standardization. |
Jasjeet S. Sekhon, UC Berkeley, sekhon@berkeley.edu, http://sekhon.berkeley.edu/.
Sekhon, Jasjeet S. 2007. ``Multivariate and Propensity Score Matching Software with Automated Balance Optimization.'' Working Paper. http://sekhon.berkeley.edu/papers/MatchingJSS.pdf
Sekhon, Jasjeet S. 2006. ``Alternative Balance Metrics for Bias Reduction in Matching Methods for Causal Inference.'' Working Paper. http://sekhon.berkeley.edu/papers/SekhonBalanceMetrics.pdf
Hollander, Myles and Douglas A. Wolfe. 1973. Nonparametric statistical inference. New York: John Wiley & Sons.
Also see summary.balanceUV
, qqstats
ks.boot
, Match
, GenMatch
,
MatchBalance
,
balanceMV
, GerberGreenImai
, lalonde
data(lalonde) attach(lalonde) foo <- balanceUV(re75[treat==1],re75[treat!=1]) summary(foo)