st: poisson regression with lexis expansion and poisgof command

[mark tracy <mark.tracy@ozemail.com.au>]

Dear All,

I am a novice learing stata......this is probably very basic but Im 
struggling  a bit.
I have a cohort study of miners developing TB who are HIV +ve or -ve 
over a 8 year study period..  I have found the best poisson regression 
model testing with LRTs I have included a lexis expansion for age of 
subject effects. The Stat manual  on poisgof  makes no mention of 
compressing the data.  I have read that ungrouped data is not correct 
for this command.

my final model looks like this  
xi:poisson _d i.hiv ageband2 i.prevtb  i.sil if sil~=.,e(y) irr

I have used the following commands to compress the data before doing the 
poisgof

preserve

. collapse (sum) _d y,by(hiv ageband2 job1 prevtb sil)

. xi:poisson _d i.hiv ageband2  i.job1 i.prevtb  i.sil if sil~=.,e(y) irr
(output ommitted)

then  poisgof

I am sorry if there is insufficient information I am not sure how much 
to  include.

Many thanks for help in this matter.

sincerely



Mark Tracy
Director and Neonatologist
Nepean Newborn Intensive Care Unit
SWAHS
Lecturer Department of Paediatrics and Childhealth
Sydney University

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