R/function.NPVEqualPPV.R

In OptimalCutpoints: Computing Optimal Cutpoints in Diagnostic Tests

function.NPVEqualPPV <-
function(data, marker, status, tag.healthy = 0, direction = c("<", ">"), control = control.cutpoints(), pop.prev, ci.fit = FALSE, conf.level = 0.95, measures.acc){
	direction <- match.arg(direction)
	difference <- abs(measures.acc$NPV[,1]-measures.acc$PPV[,1])	   
	cNPVEqualPPV <- measures.acc$cutoffs[which(round(difference,10) == round(min(difference, na.rm=TRUE),10))]
	
	optimal.difference <- min(difference, na.rm=TRUE)
	
	optimal.cutoff <- obtain.optimal.measures(cNPVEqualPPV, measures.acc)

	res <- list(measures.acc = measures.acc, optimal.cutoff = optimal.cutoff, criterion = difference, optimal.criterion = optimal.difference)
	res
}