I am in the process of performing survival analysis. My main exposure variable and 8 other variables (covariates) are time-varying. I have some experience on time-varying analysis, but each time I have had only one time-varying variable. In such cases, I would have a separate row/observation (for every individual) for every change in the value of my time-varying variable. However, with multiple time-varying variables, I am not sure how I should arrange rows. I tried to look online for this; all I found was a passing comment that the rows should be arranged such that all the variables are constant within that row. I could not find good source for this. Does it mean that I need to create separate rows if any of my time-varying (9 in total) variable changes? This seems like a lot of work, so any suggestion, link to references would be of much help? Thank you!
