I was wondering if any have advice on what the correct steps/interpretation are with regards to the following questions on Cox regression. As a side note, I am using STATA MP 15.1 to analyse the data and I am quite new to survival analyses.
Are my covariates assumed to be time-variant? I have a dataset that has quarterly info on the diversity composition of a team (gender, age & nationality). The values can be different throughout time whenever a new person joins or leaves the team. However, it is not a fixed change over time such as with a drug who's effect lessens over time for example.
I recently changed the format of my dataset, I believe this formatting is better in case I want to account for time variance. Is this correct? Below the before and after. I also have an observation per quarter, but it might be better to only have an observation when a change occurred in the diversity variables?
- My predictor variables are continuous, and using Schoenfeld residuals, the PH assumption seems to be violated. What are potential next steps I can take?
Thank you in advance for your help! Best regards, Laura