Software

1. R package “geesmv”: http://cran.r-project.org/web/packages/geesmv/

Description: The package includes the original sandwich variance estimator proposed by Liang and Zeger (1986), and eight types of more recent modified variance estimators for improving the finite small-sample performance.

2. R package “wgeesel”: http://cran.r-project.org/web/packages/geesmv/

Description: The package includes the functions for weighted GEE model fitting as well as the existing information criteria for GEE model selection in the presence of missing data under the assumption of missing at random (MAR).

3. R package “ELCIC”: https://cran.r-project.org/web/packages/ELCIC/index.html

Description: We developed a consistent and robust information criterion to conduct model selection for semiparametric models. It is free of distribution specification and powerful to locate the true model given large sample size. This package provides several usage of ELCIC with applications in generalized linear model (GLM), generalized estimating equation (GEE) for longitudinal data, and weighted GEE (WGEE) for missing longitudinal data under the mechanism of missing at random and drop-out.