thanks for helping!
I am testing a repeated measures dataset (multiple rows per participant) in a multilevel Cox regression with time-varying predictors. I'm trying to see if effects vary by assessor. My variables are:
- ID: participant ID (time independent)
- dynamic: repeated measure test score (time dependent)
- assessor: person doing assessment, nesting variable (time independent)
- intervention : binary, whether or not dynamic was followed by intervention (time dependent)
- entry: beginning of prediction interval (time dependent)
- exit: end of prediction interval (time dependent)
- flag: if survival event occurred during interval (time dependent)
I want to eventually test if interactions between dynamic and intervention vary by assessor, but starting with univariate tests, I have two questions.
First: I keep seeing two separate ways of specifying that I want the slope (of "dynamic")to vary by assessor. What is the difference between
Second: Does it make sense to test a random coefficient for a binary variable? Would that use different syntax? Would random effects be interpretable or would I go by chi-square of the models?