Matching (version 0.48)

balanceUV: Univariate Balance Tests

Description

This function provides a number of univariate balance tests. Generally, users should call MatchBalance and not this function directly.

Usage

balanceUV(Tr, Co, weights = rep(1, length(Co)), exact = FALSE)

Arguments

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.

Value

• sdiff
  This is the standardized difference which is the mean difference between treatment and control divided by the square root of the average variance (of treatment and control). The entire quantity is then multiplied by a 100.
• 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.
• pdiscordant
  The proportion of observations which are discordant.
• wc
  The object returned by wilcox.test.
• tt
  The object returned by two-sided weighted t.test.

References

Hollander, Myles and Douglas A. Wolfe. 1973. Nonparametric statistical inference. New York: John Wiley & Sons.

Sekhon, Jasjeet S. 2004. ``Balance Tests for Matching Estimators.'' Working Paper.

See Also

Also see summary.balanceUV, Match, MatchBalance, balanceMV, GerberGreenImai, lalonde

Examples

data(lalonde)
attach(lalonde)

foo  <- balanceUV(re75[treat==1],re75[treat!=1])
summary(foo)

foo  <- balanceUV(hisp[treat==1],hisp[treat!=1])
summary(foo)