I fitted a mixed model with several categorical and continuous fixed variables and 3 nested random intercepts, using a transformation of the predictor y = log(y+1) and I used the defaults contrast treatment and contrast polynomial.
The resulting coefficients are in log units meaning that the difference between the categorical (Factor) variables builted by Contr.treatment is expressed on log values but to retransform them to actual (y) values is not as straight forward as to exp(beta)-1. I am sure that this is a problem that you guys face every day but I can't find an easy way around this. The easiest way to go is to report the betas in transformed values but this is not very useful for the practical purposes of the study.
Any comments??
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