meantab: Tabulate means of covariates after matching

In designmatch: Matched Samples that are Balanced and Representative by Design

Tabulate means of covariates after matching

Description

Function for tabulating the means and other basic statistics useful to assess covariate balance after matching.

Usage

	meantab(X_mat, t_ind, t_id, c_id, exact = NULL, digits = 2)

Arguments

X_mat	matrix of covariates: a matrix of covariates used to assess balance.
t_ind	treatment indicator: a vector of zeros and ones indicating treatment (1 = treated; 0 = control).
t_id	a vector of indexes of the treated units.
c_id	a vector of indexes of the matched controls.
exact	a vector of characters equal to "f" or "w" indicating whether Fisher's exact test or Wilcoxon rank-sum test should be used for binary (or categorical) and continous covariates, respectively. Otherwise, if exact exact = NULL, simple t-tests are used. The default is exact = NULL. If exact != NULL, the length of exact has to be equal to the number of columns of X_mat.
digits	a scalar indicating the number of digits to display in the columns of the table.

Details

meantab is a function for tabulating the means and other basic statistics useful to assess covariate balance after matching.

Value

A table with the following columns:

Mis	proportion of missing values for each covariate;
Min	minimum value for each covariate;
Max	maximum value for each covariate;
Mean T	mean of the treated units for each covariate;
Mean C	mean of the matched controls for each covariate;
Std Dif	standardized differences in means after matching for each covariate;
P-val	P-values for t-tests for differences in means between treated units and matched controls for each covariate.

Examples

	# Load data
	data(germancities)

	# Sort and attach data
	germancities = germancities[order(germancities$treat, decreasing = TRUE), ]
	attach(germancities)

	# Treatment indicator
	t_ind = treat
	
	# Indexes of the treated units
	t_id = which(t_ind == 1)

	# Matrix of covariates
	X_mat = cbind(log2pop, popgrowth1939, popgrowth3339, emprate, indrate, rubble, 
	rubblemiss, flats, flatsmiss, refugees)

	# Indices of the matched controls (obtained using bmatch in designmatch)
	c_id = c(67, 75, 39, 104, 38, 93, 79, 59, 64, 55, 106, 99, 97, 61, 82, 57, 
	76, 47, 46, 49)
 
 	# meantab
	meantab(X_mat, t_ind, t_id, c_id)
	
	# meantab
	meantab(X_mat, t_ind, t_id, c_id, exact = c(rep("w", 6), "f", "w", "f", "w"), digits = 3)

designmatch documentation built on Aug. 29, 2023, 5:11 p.m.