About the OCC and Mismatch

[leslieyoungwei]

Hi, I'm having some questions about Πk and Nk/N in the formula in picture

What's the difference between these two (pi and actprop)

occ <- function(p, pi) {
    app <- appa(p)
    numerator <- app/(1 - app)
    denominator <- pi/(1 - pi)
    occ <- numerator/denominator
    return(occ)
}
mismatch <- function(p, pi) {
    # determine class
    group <- class_assignment(p)
    K <- ncol(p)
    
    # Tabulate the actual proportions
    actprop <- tabulate(group, nbins = K)/nrow(p)
    
    # Compute the mismatch (mismatch=actual-estimated)
    return(actprop - pi)
}
@param pi is the estimated proportion of class membership of length K

Thank you for your answer

Best wishes!