LogRegR2 = function(model)
{
  # version 2.0, 22-Jan-2012, Dirk Enzmann
  # Calculates multiple Rē analogs (pseudo Rē) of logistic regression:

  if ((model$family$family != "binomial") | (model$family$link != "logit"))
  {
    stop('No logistic regression model, no pseudo Rē computed\n')
  }

   n    = dim(model$model)[1]
   Chi2 = model$null - model$dev
   Df   = model$df.null - model$df.res
   p    = 1-pchisq(Chi2,Df)

   lp   = predict(model)
   var_lp = var(lp)

   RL2  = Chi2/model$null            # also called McFaddens Rē
   Cox  = 1-exp(-Chi2/n)             # Cox & Snell Index
   Nag  = Cox/(1-exp(-model$null/n)) # Nagelkerke Index
   MZ   = var_lp/(var_lp + pi^2/3)   # McKelvey & Zavoina's Rē

   list('Chi2'=Chi2,'df'=Df,'p'=p,'RL2'=RL2,'CoxR2'=Cox,'NagelkerkeR2'=Nag,'McKelvey_ZavoinaR2'=MZ)
}