The cure can be worse than the disease here. Setting a minimum can introduce biases (and slow runtime). Log-transformation can distort the relationship between variables, and there is no guarantee that the logged variables will be any closer to normal than the original variables. Often the best approach is just to hold your nose and impute non-normal variable as though they were normal. It's not optimal -- and hopefully better options will become available through PROC MI -- but often the results are not too bad.   I have written extensively about this issue in this paper:  https://pdfs.semanticscholar.org/74b4/a31619809c99866760109e00c34ba8830728.pdf ... View more