CoxBcv.mbn {CoxBcv} R Documentation

## Morel, Bokossa, and Neerchal (MBN) bias-corrected sandwich variance estimator

### Description

Calculate the Morel, Bokossa, and Neerchal (MBN; 2003) bias-corrected sandwich variance estimator, for marginal Cox analysis of cluster randomized trials, proposed by Wang et al. (under review).

### Usage

CoxBcv.mbn(Y, Delta, X, ID)

### Arguments

 Y vector of observed time-to-event data. Delta vector of censoring indicators. X matrix of marginal mean covariates with one column for one covariate (design matrix excluding intercept). ID vector of cluster identifiers.

### Value

• coef - estimate of coefficients.

• exp(coef) - estimate of hazard ratio.

• MBN-var - MBN bias-corrected sandwich variance estimate of coef.

### References

Morel, J. G., Bokossa, M. C., & Neerchal, N. K. (2003). Small sample correction for the variance of GEE estimators. Biometrical Journal: journal of mathematical methods in biosciences, 45(4), 395-409.

Wang, X., Turner, E. L., & Li, F. Improving sandwich variance estimation for marginal Cox analysis of cluster randomized trials. Under Review.

### Examples

Y <- c(11,19,43,100,7,100,100,62,52,1,7,6)
Delta <- c(1,1,1,0,1,0,0,1,1,1,1,1)
X1 <- c(0,0,0,0,0,0,1,1,1,1,1,1)
X2 <- c(-19,6,-25,48,10,-25,15,22,17,-9,45,12)
ID <- c(1,1,2,2,3,3,4,4,5,5,6,6)

X <- X1
CoxBcv.mbn(Y,Delta,X,ID)

X <- cbind(X1,X2)
CoxBcv.mbn(Y,Delta,X,ID)

[Package CoxBcv version 0.0.1.0 Index]