Hi, I'm "playing" a bit with the vignette on customMethods in the affy package. If I try to replicate the example (or doing my own) for a new method for summary expression (i.e. "huber"), I get: expresso(mydata,bg.correct=F,normalize=F,summary.method="huber") ## just a trial ... ... Error in computeExprSet(afbatch, summary.method = summary.method, pmcorrect.method = pmcorrect.method, : no direct or inherited method for function 'computeExprSet' for this call Any hint? TIA, Stefano -- Stefano Calza, PhD Sezione di Statistica Medica e Biometria Dip. di Scienze Biomediche e Biotecnologie Universit? degli Studi di Brescia - Italia Viale Europa, 11 25123 Brescia email: calza at med.unibs.it Telefono/Phone: +390303717532 Fax: +390303717488 Section of Medical Statistics and Biometry Dept. Biomedical Sciences and Biotechnology University of Brescia - Italy