R/Reardon.R

In agrmt: Calculate Concentration and Dispersion in Ordered Rating Scales

Reardon = function(V) {
  # Calculate Reardon's (2009) entropy
  K = length(V)
  Fi = cumsum(V/sum(V))
  summand = Fi*log2(1/Fi) + (1 - Fi)*log2(1/(1 - Fi))
  summand[is.na(summand)] = 0 # NA from log2() replaced
  r = (1/(K-1)) * sum(summand[1:(K-1)]) # sum only the first K-1 terms
  return(r)
}