My data set looks like this
ID Weak_year Strong_year Covariate1 Covariate2 ... 1 1966 NA 0.35 0.29 1 NA 1987 0.97 1.20 2 NA 1970 0.76 0.90 3 1975 NA 1.4 3.2 4 ... ...
So each object can produce either a weak reaction, a strong reaction, or a weak and then strong reaction. Weak_year is the year a weak reaction happens, strong_year is the year a strong reaction happens. The covariates are independent variables; their values are the values for the year that the reaction events happened.
The start of the study is 1965 and the censoring time is 1990. Some observations are right-censored.
I'm familiar with survival analysis of binary outcomes (event or non-event), but I'm not sure how to model the time to event when there are three outcome levels of different strengths like these. What are some options to think about? It would be especially useful if these options can be implemented in R (that's what I'm using).