Centered time variable as random slope?

[louise macgregor]

For random slope longitudinal mixed level models, should you use the centered/linear time variable as was used as a covariate, or non-linear and non-centered time for the random slope?
Thanks for your help!

[Clyde Schechter]

I'm not sure I understand the question, nor why you are asking it. But whenever you include a random slope in a multi-level model, the exact same variable should also appear as a covariate in the fixed (bottom) level of the model. So if time is centered in the bottom level of the model, then you should use centered time as the random slope. If time was introduced with linear and quadratic terms among the covariates, then time random slopes should include the linear and quadratic terms as well.