plotROCcurveTri {CoRpower} R Documentation

Plotting of ROC Curves for Trichotomous Biomarkers

Description

Plots the receiver operating characteristic (ROC) curve displaying sensitivity and specificity for a range of `P2` and `P0` values, four values of `rho`, and four values of `Plat2`. Illustrates how different levels of measurement error `rho` map to sensitivity and specificity, depending on the value of `Plat2`. This funciton is used to create Figure 1 in the Supplementary Material of [Gilbert, Janes, and Huang (2016). "Power/Sample Size Calculations for Assessing Correlates of Risk in Clinical Efficacy Trials."]

Usage

```plotROCcurveTri(Plat0, Plat2, P0, P2, rho)
```

Arguments

 `Plat0` a numeric value specifying the prevalence of the latent lower protected subgroup for a dichotomous or trichotomous biomarker `Plat2` a numeric vector of length four specifying the prevalences of the latent higher protected subgroup for a dichotomous or trichotomous biomarker `P0` a numeric vector specifying a grid of probabilities of low biomarker response for a dichotomous or trichotomous biomarker. `P2` a numeric vector specifying a grid of probabilities of high biomarker response for a dichotomous or trichotomous biomarker. `rho` a numeric vector of length four specifying distinct protection-relevant fractions of `sigma2obs`.

Value

None. The function is called solely for plot generation.

Examples

```Plat0 <- 0.2
Plat2 <- c(0.2, 0.3, 0.4, 0.5)
P0 <- seq(0.90, 0.10, len=10)
P2 <- seq(0.10, 0.90, len=10)
rho <- c(1, 0.9, 0.7, 0.5)
plotROCcurveTri(Plat0 = Plat0, Plat2 = Plat2, P0 = P0, P2 = P2, rho = rho)

```

[Package CoRpower version 1.0.4 Index]