Computes the standardized mean difference between two groups. This is a key metric for assessing balance in matched samples.
standardized_difference(x1, x2, pooled = TRUE)Numeric value representing the standardized difference
Numeric vector for group 1
Numeric vector for group 2
Logical, if TRUE use pooled standard deviation (default), if FALSE use group 1 standard deviation
Standardized difference = (mean1 - mean2) / pooled_sd where pooled_sd = sqrt((sd1^2 + sd2^2) / 2)
Common thresholds: less than 0.1 is excellent balance, 0.1-0.25 is good balance, 0.25-0.5 is acceptable balance, and greater than 0.5 is poor balance.