cv_auc: Cross-validated area under the receiver operating...

Description Usage Arguments Details Value Examples

View source: R/auc_functions.R

Description

This function computes K-fold cross-validated estimates of the area under the receiver operating characteristics (ROC) curve (hereafter, AUC). This quantity can be interpreted as the probability that a randomly selected case will have higher predicted risk than a randomly selected control.

Usage

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cv_auc(Y, X, K = 10, learner = "glm_wrapper", nested_cv = TRUE,
  nested_K = K - 1, parallel = FALSE, max_cvtmle_iter = 10,
  cvtmle_ictol = 1/length(Y), prediction_list = NULL, ...)

Arguments

Y

A numeric vector of outcomes, assume to equal 0 or 1.

X

A data.frame or matrix of variables for prediction.

K

The number of cross-validation folds (default is 10).

learner

A wrapper that implements the desired method for building a prediction algorithm. See TODO: ADD DOCUMENTATION FOR WRITING

nested_cv

A boolean indicating whether nested cross validation should be used to estimate the distribution of the prediction function. Default (TRUE) is best choice for aggressive learner's, while FALSE is reasonable for smooth learner's (e.g., logistic regression).

nested_K

If nested cross validation is used, how many inner folds should there be? Default (K-1) affords quicker computation by reusing training fold learner fits.

parallel

A boolean indicating whether prediction algorithms should be trained in parallel. Default to FALSE.

max_cvtmle_iter

Maximum number of iterations for the bias correction step of the CV-TMLE estimator (default 10).

cvtmle_ictol

The CV-TMLE will iterate max_cvtmle_iter is reached or mean of cross-validated efficient influence function is less than cvtmle_ictol.

prediction_list

For power users: a list of predictions made by learner that has a format compatible with cvauc.

...

Other arguments, not currently used

Details

To estimate the AUC of a particular prediction algorithm, K-fold cross-validation is commonly used. The data are partitioned into K distinct groups. The prediction algorithm is developed using K-1 of these groups. In standard K-fold cross-validation, the AUC of this prediction algorithm is estimated using the remaining fold

Value

A list TO DO: More documentation here

Examples

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n <- 200
p <- 10
X <- data.frame(matrix(rnorm(n*p), nrow = n, ncol = p))
Y <- rbinom(n, 1, plogis(X[,1] + X[,10]))
fit <- cv_auc(Y = Y, X = X, K = 5, learner = "glm_wrapper")

benkeser/predtmle documentation built on May 20, 2019, 5:41 p.m.