Doc, Thank you very much for the reply. I think I'm on the brink of 'getting it' but I just want to be sure. I did run a paired t-test on the means of each construct (as an aside, it worked very, very well, as far as supporting my story). However, I was thinking an interesting post-hoc analysis might be to take the examination a little deeper by also looking at how the relationships between factors (5 predictors 1 outcome) change after the treatment. For example, one of the predictor variables is trust and the outcome variable is purchase intention. The paired t-test revealed that after treatment, the means for both variables went up significantly (in the statistical sense). I'm wondering now, if the relationship between these two variables also changed. Would the approaches you describe above, regarding the use of difference scores, work for this analysis and provide added insight the t-test doesn't, if I don't include covariates? Thanks again for the help
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