I have the following data set:
Row Patient Freq of Sickness Sick # of times(2 yrs) Symp 1 Symp 2 Sym 3 1 A 60 days 4 1 0 1 2 B 90 days 10 0 1 1 3 C 40 days 5 0 0 6 4 D 30 days 0 1 0 0 5 E 80 days 1 3 0 1
What kind of logistic regression should I use if I need to predict the probability for each patient to be sick in the next year ? Also, need to calculate the maximum likelihood and odds ratio of each symp which contributes to the sickness.
Should I consider Sick # of times(2 yrs) as ordinal or nominal ? I think Ordinal.
Presently, I am using PROC Logistic and PROC GENMOD in SAS to solve this problem. In GENMOD i used Cumulative logit and in PROC Logistic I have tried using both Ordered logit and un ordered Glogit. I got the best results when I used cumulative logit.
Any reference to study material would be highly appreciated.
Also is Logistic Regression the correct approach?