R/RRlog_check.R

In RRreg: Correlation and Regression Analyses for Randomized Response Data

checkPerfectSeparation <- function(y, x, n.response) {
  for (i in 1:ncol(x)) {
    if (length(unique(x[, i])) != 1) {
      xorder <- order(x[, i])
      checkSeparation <- all(y[xorder] == sort(y[xorder])) |
        all(rev(y[xorder]) == sort(y[xorder]))
      if (checkSeparation) {
        warning(
          "A covariate (i.e., ", colnames(x)[i], ") perfectly separates",
          "\n  responsess of the RR-variable, which will probably lead to unstable estimates."
        )
      }
    }
  }
}