# calc_risk: Calculate the risk and functions of the risk In pseval: Methods for Evaluating Principal Surrogates of Treatment Response

## Description

Computes the treatment efficacy (TE) and other functions of the risk in each treatment arm over the range of surrogate values observed in the data. TE(s) is defined as 1 - risk(s, z = 1)/risk(s, z = 0), where z is the treatment indicator. If any other variables are present in the risk model, then the risk is computed at their median value.

## Usage

 ```1 2 3``` ```calc_risk(psdesign, contrast = "TE", t, sig.level = 0.05, CI.type = "band", n.samps = 5000, bootstraps = TRUE, newdata = NULL) ```

## Arguments

 `psdesign` A psdesign object. It must contain a risk model, an integration model, and estimated parameters. Bootstrapped parameters are optional `contrast` The contrast function, or the name of the contrast function. See details. `t` For time to event outcomes, a fixed time `t` may be provided to compute the cumulative distribution function. If not, the restricted mean survival time is used. Omit for binary outcomes. `sig.level` Significance level for bootstrap confidence intervals `CI.type` Character string, "pointwise" for pointwise confidence intervals, and "band" for simultaneous confidence band. `n.samps` The number of samples to take over the range of S.1 at which the contrast is calculated `bootstraps` If true, and bootstrapped estimates are present, will calculate bootstrap standard errors and confidence bands. `newdata` Vector of S values. If present, will calculate the contrast function at values of newdata instead of the observed S.1

## Details

The contrast function is a function that takes 2 inputs, the risk_0 and risk_1, and returns some one dimensional function of those two inputs. It must be vectorized. Some built-in functions are `"TE"` for treatment efficacy = 1 - risk_1(s)/risk_0(s), `"RR"` for relative risk = risk_1(s)/risk_0(s), `"logRR"` for log of the relative risk, and `"RD"` for the risk difference = risk_1(s) - risk_0(s).

## Value

A data frame containing columns for the S values, the computed contrast function at S, R0, and R1 at those S values, and optionally standard errors and confidence intervals computed using bootstrapped estimates.

## Examples

 ```1 2 3 4 5 6``` ```## Not run: # same result passing function name or function calc_risk(binary.boot, contrast = "TE", n.samps = 20) calc_risk(binary.boot, contrast = function(R0, R1) 1 - R1/R0, n.samps = 20) ## End(Not run) ```

pseval documentation built on May 2, 2019, 2:01 a.m.