A note on Jorgensen's iteratively defined statistics

Abstract

SUMMARY The Newton-Raphson and Fisher scoring iteratively reweighted least squares methods are two fundamental tools for computing parameter estimators and deletion diagnostics. Jorgensen (1993) proposed a modified method to compute deletion diagnostics. In this paper, we study the relationship between Jorgensen's, Newton-Raphson and Fisher scoring one-step deletion estimators by using the observed and expected Fisher information matrices. In addition, we extend Jorgensen's true leverage and approximate leverage from binary regression models to general model settings.