[log in to unmask]" type="cite">PSYCH-POSTGRADS Digest - 13 Apr 2010 to 15 Apr 2010 (#2010-65) Hi, I've got creeping doubts over the way I've been writing up my stats and I hope someone is feeling like they want to be a sage this morning. For a reason I'm no longer confident about I've been using unstandardised co-efficients to report multiple regression and hierarchical multiple regression and I'm now thinking that's maybe wrong.Here's the background: I've scaled several likert-style questions (post factor analysis). These had arbitrary negatives so couldn't be scaled using SPSS but were done manually, and I centred rather than standardized the scales because I was planning to do moderation analysis (and if you standardise you risk over-correlation when you make the interaction terms).I should mention that some of these variables had differing maximum scores, due to the number of questions retained after factor analysis and because some questions had different numbers of answer options.I've followed advice in Frazier et al (2004) that when reporting moderation the coefficients aren't properly standardised and are uninterpretable so you should report the unstandardised coefficients.For reasons of consistency I thought I'd write up all of my results using unstandardised coefficients, including the multiple regressions without interaction terms. I have read in so many other places that you should 'always' report the standardised co-efficients that I'm starting to have doubts.So my first question is - should I be consistent or correct - for my main effects is unstandardised ok?I've also drawn an illustration of the effects of interaction for different groups. The moderator variable was measured on a 10 point scale and the dependent variable on a 16 point scale (and they're both centred on 0). My second question is, if I use the unstandardised coefficients to mark the slopes will it be a true representation or exaggerated?I hope that makes sense. Any thoughts or advice that could unfuddle my brain would be very welcome.Reference: FRAZIER, P. A., TIX, A. P. & BARRON, K. E. (2004) Testing Moderator and Mediator Effects in Counseling Psychology Research. Journal of Counseling Psychology, 51, 115-134.
Caroline WilsonPhD Research StudentInstitute of Energy and Sustainable Development
De Montfort University
UK