# icpowerpf: Study design in the presence of interval censored outcomes... In icensmis: Study Design and Data Analysis in the Presence of Error-Prone Diagnostic Tests and Self-Reported Outcomes

## Description

This function implements power and sample size calculations for interval censored time-to-event outcomes, when the diagnostic tests are assumed to be perfect (i.e. sensitivity=1 and specificity=1). This is a special case of the more general study design function `icpower`. However, for the special case of perfect diagnostic tests, this function can be used with significantly improved computational efficiency.

## Usage

 ```1 2``` ```icpowerpf(HR, survivals, N = NULL, power = NULL, rho = 0.5, alpha = 0.05, pmiss = 0) ```

## Arguments

 `HR` hazard ratio under the alternative hypothesis. `survivals` a vector of survival function at each test time for baseline(reference) group. Its length determines the number of tests. `N` a vector of sample sizes to calculate corresponding powers. If one needs to calculate sample size, then set to NULL. `power` a vector of powers to calculate corresponding sample sizes. If one needs to calculate power, then set to NULL. `rho` proportion of subjects in baseline(reference) group. `alpha` type I error. `pmiss` a value or a vector (must have same length as survivals) of the probabilities of each test being randomly missing at each test time. If pmiss is a single value, then each test is assumed to have an identical probability of missingness.

## Value

same form as returned value of `icpower`

## Note

See `icpower` for more details in a general situation.

## Examples

 ```1 2 3 4 5 6 7 8 9``` ```powpf1 <- icpowerpf(HR =2 , survivals = seq(0.9, 0.1, by=-0.1), N = NULL, power = 0.9, pmiss = 0) powpf2 <- icpowerpf(HR =2 , survivals = seq(0.9, 0.1, by=-0.1), N = NULL, power = 0.9, pmiss = 0.7) ## Different missing probabilities at each test time powpf3 <- icpowerpf(HR =2 , survivals = seq(0.9, 0.1, -0.1), N = NULL, power = 0.9, pmiss = seq(0.1, .9, 0.1)) ```

icensmis documentation built on May 29, 2017, 10:11 p.m.