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Mplus Discussion > Structural Equation Modeling >
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 Scott Colwell posted on Monday, April 04, 2005 - 3:35 pm
I am running a moderation of one observed continous variable Z on the path between latent variable X on latent variable Y. The continuous variable Z is a stated percentage of usage of self service technology (SST) rated from 0% to 100% of the time. Since this variable does not follow a normal distribution, I thought it would be best to do a log transformation (base10) of Z prior to running the interaction. This leads me to two questions:

1) Can I write the code for the transformation in the command syntax or do I have to do it in the raw data? If possible in the syntax, where would I find sample code?

2) Would the log transformation cause problems with the estimation? ie: give improper estimates.

Thanks,
 Linda K. Muthen posted on Wednesday, April 06, 2005 - 2:59 am
You can use the DEFINE command to do the log transformation. The log transformation would not cause estimation problems.
 Snigdha Dutta posted on Monday, July 22, 2019 - 5:31 am
How well does Mplus cope with violations of linearity? Using MLR with non-normal and skewed ordinal data.

Two of my IVs have high floor effects.
My model fit remains poor and unchanged even after removing non-significant paths. I'm trying to think of what could be biasing the model.
 Bengt O. Muthen posted on Tuesday, July 23, 2019 - 5:58 pm
Skewed IV distribution does not necessarily cause problems. It is mostly relevant for DVs. If the DVs are treated as ordinal, skewness is not an issue.
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