Hi, I have a this program to calculate the hospital use according to the number of disease and the age. The number of disease has been coded into 5 categories (0 to 4) and the age also has 5 categories (1 (youngest) to 5(oldest)). We also added an interaction term between age and number of disease. I'm trying to calculate the difference between the oldest and the youngest group for each category of disease. I know we van use the lsmestimate procedure but I'm having a hard time to figure out where to place the zeros and ones, etc. This is my code :   Thank you    PROC LOGISTIC desc DATA=exemple; Class disease (ref='0') age (ref='1')/ param=glm; Model hospital = disease age disease*age; lsmeans disease age disease*age/ diff ilink cl e exp; lsmestimate 'diff age 5 - age 1 for disease = 0' 0 0 0 0 0  1 0 0 0 -1/ ilink cl e exp; lsmestimate 'diff age 5 - age 1 for disease = 1' 0 1 0 0 0  1 0 0 0 -1/ ilink cl e exp; lsmestimate 'diff age 5 - age 1 for disease = 2' 0 0 1 0 0  1 0 0 0 -1/ilink cl e exp; lsmestimate 'diff age 5 - age 1 for disease = 3' 0 0 0 1 0  1 0 0 0 -1/ilink cl e exp; lsmestimate 'diff age 5 - age 1 for disease = 4' 0 0 0 0 1  1 0 0 0 -1/ilink cl e exp; RUN; ... View more