R/calculateCoeffs.polr.R

In pbiecek/PISAtools: A set of tools useful when dealing with PISA data.

calculateCoeffs.polr <- function(model, datas, method="probit", weigths = NULL, fweigth, starts = NULL) {
  if (is.null(starts)) {
    mres <- polr(model, datas, weights=datas[,fweigth], method=method)
  } else {
    mres <- polr(model, datas, weights=datas[,fweigth], method=method, start=starts)
  }
  starters <- c(mres$coefficients, mres$zeta)
  
  if (is.null(weigths)) {
    mresAll <- NULL
    se <- NULL
  } else {
    mresAll <- sapply(seq_along(weigths), function (i) {
      datas$wei <- datas[,weigths[i]]
      mresW <- polr(model, datas, weights=wei, method=method)
      c(mresW$coefficients, mresW$zeta)
    })
    se <- sqrt(rowMeans((mresAll - starters)^2))/sqrt(length(weigths))
  }
  
  list(coeffs = starters, se = se, allCoefs = mresAll)
}