There seems to be a lot of discussion about this on CV but none quite answer my question.
I have a variable
y which represents number of adverse events occurring within a four-week period. There are three types of adverse event: 'mild', 'moderate' and 'severe' (and of course 'none').
There are three four-week periods. Thus each participant will have a count of number of each of the three incidents in each four-week period.
Now for my question. What regression model would be best here? A multilevel random slopes GLM with ID as the random factor and period (1 - 3) and experimental group (placebo vs treatment) as the fixed factors seems appropriate, but what sort?
Both poisson and multinomial logistic regression deal with incidences (i.e. odds of occurence) of discrete outcomes, but I am not really sure what category my analysis falls into. If the outcome was a binary one (i.e. a single event type and you either experience or don't) then it would be poisson/Negative binomial for certain. But the fact that there are three possible events has me at a loss for what analysis to run.
Any help appreciated.