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Dear SPM Group and John West, we are currently trying the same (ANCOVA with mutliple covariates) and do not get it work, too. Does anybody of the SPM Group have something like a manual for the ANCOVA procedure in SPM2??? Thanks a lot, Alexander Diehl, MD Central Institute of Mental Health, Mannheim, Germany John D. West schrieb: >Dear SPM group: > >We are currently trying to setup an ANCOVA with multiple covariates for VBM. Unfortunately, the basic ANCOVA in SPM2 appears to only permit one covariate (as a nuisance variable). > >We could use any suggestions you might have to setup this analysis. > >The basics of the VBM analysis we wish to perform are as follows: >There are two between subjects factors that we wish to investigate in a 2 X 3 design yielding 6 independent cells (Factor A with level 1 and 2 and Factor B with level 1, 2, and 3). >We think that the best design to use would be to combine these factors so that we have 6 groups. (11 12 13 21 22 23). We also want to covary for 3 other potential confounding variables (age, sex, ICV). It seems that we could do this by using a multiregression analysis and a combination of dummy variables to code for the six groups. However, it seems to us that we would lose the ability to look at paired contrasts betwen subgroups (e.g. 11 vs 12) and to extract the adjusted data for profiling the results. Similar issues have come up with complex fMRI models. > >Any suggestions on how to compute a complex factorial design with multiple covariates would be most appreciated. > >Thank you in advance. >John West >Brain Imaging Lab, DHMC > > > -- Dr. med. Alexander Diehl Oberarzt Klinik für Abhängiges Verhalten und Suchtmedizin Zentralinstitut für Seelische Gesundheit Universität Heidelberg J5, D 68159 Mannheim Tel.: +49 / 621 1703-3542 Fax: +49 / 621 1703-3905 email: [log in to unmask] home: www.zi-mannheim.de