I'm running a multiple hierarchical regression in the social sciences. Any thoughts on the following questions:

1. For interaction effects, A X B where both are interval data ... if one variable requires transformation, how should I handle centering the data? If the variables are fairly well behaved and fit normality assumptions, is it ok to run the regression without centering (and with one variable transformed)?

2. One of these interaction terms is a scale, made up of 2 subscales, for which I want to test whether it moderates the effect between two other varialbes. If one of the subscales needs transformation, but the full scale and other subscale do not ... is it ok to run the analyes this way (i.e. 3 separate times, looking at interaction effects for each subscale and the total scale for each run)

Cheers,

M.R.