compute_sigma {rbmi} | R Documentation |
Compute covariance matrix for some reference-based methods (JR, CIR)
Description
Adapt covariance matrix in reference-based methods. Used for Copy Increments in Reference (CIR) and Jump To Reference (JTR) methods, to adapt the covariance matrix to different pre-deviation and post deviation covariance structures. See Carpenter et al. (2013)
Usage
compute_sigma(sigma_group, sigma_ref, index_mar)
Arguments
sigma_group |
the covariance matrix with dimensions equal to |
sigma_ref |
the covariance matrix with dimensions equal to |
index_mar |
A logical vector indicating which visits meet the MAR assumption for the subject. I.e. this identifies the observations that after a non-MAR intercurrent event (ICE). |
References
Carpenter, James R., James H. Roger, and Michael G. Kenward. "Analysis of longitudinal trials with protocol deviation: a framework for relevant, accessible assumptions, and inference via multiple imputation." Journal of Biopharmaceutical statistics 23.6 (2013): 1352-1371.