I am using a longitudinal survey panel as my data source to run a Cox regression. The survey is administered biannually. Based on some previous research, the number of children in the household is seen as an important factor in whether the event occurs or not, and this, of course, is a time varying covariate. In the case of uncensored observations, it seems fairly logical to pull that data point from the most recent survey--that is if the event occurred in 2020, I could use the children present in 2018.
In the case of censored observations, however, I'm not entirely sure from which time point to pull the data. For observations that have not experienced the event, should the data be pulled from the most recent wave of the survey (2020)? For censored observations that were lost due to drop out, do I use the data most recently available?