VarClosed_Li: Closed formula for treatment variance, with proportional...

In PMildenb/SteppedPower: Power Calculation for Stepped Wedge Designs

Closed formula for treatment variance, with proportional decay

Description

From Li et al "Design and analysis considerations for cohort stepped wedge cluster randomized trials with a decay correlation structure"

Usage

VarClosed_Li(trtMat, tau, psi, N, AR)

Arguments

trtMat	a matrix trtMat to define treatment allocation, where rows and columns correspond to cluster and timepoints, respectively
tau	numeric, standard deviation of random intercepts
psi	numeric, random subject specific intercept.
N	numeric, number of individuals per cluster.
AR	numeric (scalar), It defines the AR(1)-correlation of random effects.

Value

numeric, variance of the estimator for treatment effect

Examples

##  test setting, from Hussey&Hughes 2007  ####
trtMat <- construct_DesMat(c(6,6,6,6))$trtMat
tau <- .025 ; N <- 100 ; psi <- .1 ; AR <- .6
tmp <- VarClosed_Li(trtMat, tau=tau, psi=psi, N=N, AR=AR)
tTestPwr((.05-.032), se=sqrt(tmp), Inf)
glsPower(Cl=rep(6,4), mu0=.05, mu1=.032, AR=AR,
         tau=tau, N=N, sigma=0, psi=psi, verbose=0)

PMildenb/SteppedPower documentation built on Sept. 20, 2023, 4:57 a.m.