Abstract: Generalised estimating equations method has been widely applied to longitudinal data analysis. The resulting estimators are consistent whether the true correlation matrix is specified or misspecified. However, when the working correlation matrix is far away from the true one, the efficiency will be low. In order to reduce the influence of the choice of working correlation matrices in terms of efficiency, quadratic inference functions method and hybrid generalised estimating equations method have been proposed. In this paper, several simulation studies are conducted to compare the hybrid generalised estimating equations method with the quadratic inference functions method.

Key words: generalised estimating equations, quadratic inference functions, Hybrid GEE