# Compute the sample size for standard win ratio test Compute the sample size for standard win ratio test. ```r WRSS(xi, bparam, q = 0.5, alpha = 0.05, side = 2, power = 0.8) ``` ## Arguments - `xi`: A bivariate vector of hypothesized component-wise (treatment-to-control) log-hazard ratios under the Gumbel--Hougaard copula model described in `base`. - `bparam`: A list containing baseline parameters `zeta2` for $\zeta_0^2$ and `delta` for $\boldsymbol\delta_0$; Can directly use the output of base . - `q`: Proportion of patients assigned to treatment. - `alpha`: Type I error rate. - `side`: 2-sided or 1-sided test. - `power`: Target power. ## Returns A list containing `n`, the computed sample size. ## Examples ```r # The following is not run in package checking to save time. ## Not run: ## load the package and pilot dataset library(WR) head(hfaction_cpx9) dat<-hfaction_cpx9 ## subset to control group pilot<-dat[dat$trt_ab==0,] ## get the data ready for gumbel.est() id<-pilot$patid ## convert time from month to year time<-pilot$time/12 status<-pilot$status ## compute the baseline parameters for the Gumbel--Hougaard ## copula for death and hospitalization gum<-gumbel.est(id, time, status) ## get the baseline parameters lambda_D<-gum$lambda_D lambda_H<-gum$lambda_H kappa<-gum$kappa ## set up design parameters and use base() ## to calculate bparam for WRSS() # max follow-up 4 years tau<-4 # 3 years of initial accrual tau_b<-3 # loss to follow-up rate lambda_L=0.05 # compute the baseline parameters bparam<-base(lambda_D,lambda_H,kappa,tau_b,tau,lambda_L) bparam ## sample size with power=0.8 under hazard ratios ## 0.9 and 0.8 for death and hospitalization, respectively. WRSS(xi=log(c(0.9,0.8)),bparam=bparam,q=0.5,alpha=0.05, power=0.8)$n ## sample size under the same set-up but with power 0.9 WRSS(xi=log(c(0.9,0.8)),bparam=bparam,q=0.5,alpha=0.05, power=0.9)$n ## End(Not run) ``` ## References Mao, L., Kim, K. and Miao, X. (2021). Sample size formula for general win ratio analysis. Biometrics, https://doi.org/10.1111/biom.13501. ## See Also `gumbel.est`, `base`

WRSS function