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Dear all, I 'm doing a conjoint analysis in spss and I have the following problem: I know in advance the relationships in the levels of the factors (This is confirmed by expert people who are also doing the ranking of cards and any other relationship maybe anacceptable by them). If I use the (disctrete) model for the levels I get some relationships that are not in the right direction but the Pearson' R is really great both for design cases and holdouts (0.995 and 0.667 respectively). If I postulate a linear model the problem is fixed but Pearson's R goes down (0.65 and 0.33 respectively). One option is to use the latter model but I wonder if this problem indicates that something is wrong with the ranking of cards or the number of cards in the orthogonal is not adequate (27 design + 4 holdouts=31 cards for 10 factors with 3 levels each). Is there any possible solution? I 'm also interested in a good book in Conjoint Analysis. Thanks in advance Christos