© 2002 by Biometrika Trust
Influence functions and outlier detection under the common principal components model: A robust approach
1 Conicet, Departamento de Matemática and Instituto de Cálculo, Ciudad Universitaria, Pabellón 1, Buenos Aires, C1428EHA, Argentina gboente{at}mate.dm.uba.ar 2 Departamento de Matemática, Instituto Superior Técnico, Av.Rovisco Pais, 1049-001 Lisboa, Portugal ana.pires{at}math.ist.utl.pt isabel.rodrigues{at}math.ist.utl.pt
The common principal components model for several groups of multivariate observations assumes equal principal axes but different variances along these axes among the groups.Influence functions for plug-in and projection-pursuit estimates under a common principal component model are obtained. Asymptotic variances are derived from them. Outlier detection is possible using partial influence functions.
Key Words: Asymptotic variance; Common principal components; Partial influence function; Projection-pursuit; Robust estimation; Robust scatter matrix
Received August 2001. Revised February 2002