In the presence of data contamination or outliers, some empirical studies have indicated that the two methods of generalised estimating equations and quadratic inference functions appear to have rather different robustness behaviour. This paper presents a theoretical investigation from the perspective of the influence function to identify the causes for the difference. We show that quadratic in...

Background: Infantile colic is defined as episodes of extreme and excessive crying due to unknown causes. Various results have been reported regarding the management of colic with probiotics in terms of effectiveness, with no side effects or health risks in the infants. The present study aimed to evaluate the effect of probiotics on the infants with colic using the quadratic inference functions...

background: the celebrated generalized estimating equations (gee) approach is often used in longitudinal data analysis. while this method behaves robustly against misspecification of the working correlation structure, it has some limitations on efficacy of estimators, goodness-of-fit tests and model selection criteria. the quadratic inference functions (qif) is a new statistical methodology tha...

Empirical likelihood ratio method (Thomas and Grunkmier 1975, Owen 1988, 1990, 2001) is a general nonparametric inference procedure that has many nice properties. Recently the procedure has been shown to also work with censored data with various parameters and the nice properties also hold there. But the computation of the empirical likelihood ratios with censored data and/or complex setting is...

A class of martingale estimating functions is convenient and plays an important role for inference for nonlinear time series models. However, when the information about the first four conditional moments of the observed process becomes available, the quadratic estimating functions are more informative. In this paper, a general framework for joint estimation of conditional mean and variance para...