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Report, 2011

Local influence analysis in 2 x 2 cross-over designs

Hao, Chengcheng; von, Rosen Tatjana; von, Rosen Dietrich


The aim of this work is to develop new methodology to detect influential observations in cross-over design models with random individual effects. Various case-weighted perturbations are performed. We derive the exact solution of influence of the perturbations on each parameter estimate and their dispersion matrix. Closed-form maximum likelihood estimates (MLEs) of variance parameters as well as fixed effect parameters in the cross-over design models are utilised. The work exhibits the possibility to produce closed-form expressions of the influence using the residuals in mixed models. A discussion on restrictions of the case-weighted perturbation schemes is given. Some graphical tools are also presented.


cross-over design modelling; explicit maximum likelihood estimate; influential observation; mixed linear model; perturbation scheme; statistical diagnostics

Published in

Research report - Department of Statistics, University of Stockholm
2011, number: 2011:1
Publisher: Department of Statistics, Stockholm University