ROCplots: ROCplots

Description

A variety of ROC-related plots for a binary target and a single continuous predictor.

Usage

ROCplots(data, whichPlots = c("density", "raw", "ROC", "pv", "nnt", "nntRange"), NNTlower = 3, NNTupper = 10, N = 1000, prev = 0.2, diffInSD = 2, ...)

Arguments

data

Data frame with columns "class" (binary target variable) and "X" (predictor).

whichPlots

Which plots to do. Options are c("density", "raw", "ROC", "pv", "nnt")

NNTlower

Subjective input. If NNT < NNTlower, the decision is clearly to Treat.

NNTupper

Subjective input. If NNT > NNTupper, the decision is clearly to Wait.

For simulated data: sample size

For simulated data: Prevalence

diffInSD

For simulated data: Difference: E(X | group=1) - E(X | group=0),measured in units of S.D (common to the 2 groups).

...

Extra arguments for a plot. Do not supply unless length(whichPlots)==1.

Details

The plots display the values achievable by changing the cutoff, in comparison with the desired values as determined by NNTlower and NNTupper. The "whichPlots" options are as follows:

"density"Marginal density of X, with rug.
"raw"X versus class.
"ROC"Standard ROC curve.
"pv"Plot of ppv versus npv, with indication of the acceptable range for cutoff.
"nnt"Plot of NNTpos versus NNTneg, with indication of the acceptable region
"nntRange"Plot of NNTpos and NNTneg versus cutoff, with indication of the acceptable range.
By default, all the plots are made.