SPSS – Problem with Poisson Model for Rates


New Member
Dear all,

I have recently been given a piece of SPSS-based coursework, and with the deadline coming into view I am stuck on the data entry section.

I have been given two tables of data: Table 1 presents the number of cases of insulin-dependent diabetes mellitus (IDDM) by sex, age and geographical area.
Table 2 presents the estimated population at risk by sex, age and geographical area.
There are 6 areas and 3 age groups (0-4, 5-9 , 10-17), and both cases and populations are counted separately for Males and Females.

I am meant to enter the data appropriately into SPSS and then select a suitable Poisson model for the IDDM rates given age, sex and area. To do this, I would have to calculate a constant parameter in order to create the initial constant rates model, and then expand on it.

Unfortunately, the only Poisson model for rates I have as a guide has gender-neutral cases and population at risk – not separate for males and females like in this case. As a result, I am not sure how to input the data into SPSS:
if I put in separate male and female data, I will get two different constants which will require a model each (I have to limit myself to one); but if I merge the male and female data in order to get a single constant, the model will no longer be able to highlight differences between male and female rates, making it more imprecise.

Does anyone have suggestions on how to solve this dilemma?

Many thanks in advance!