Sorry this model gives the SIRs
.xi, noomit:glm _d i.timeperiod if E!=0,fam(pois) lnoffset(E) eform
noconstant
and this one gives the p-trend:
.xi :glm _d timeperiod if E!=0,fam(pois) lnoffset(E) eform
or you could use .streg or .poisson
Raoul
On 18/10/2007, raoul reulen <[email protected]> wrote:
> Hi
>
> I'm not exactly sure what you want to do, but the title of the message
> suggests you want to do a test for linear trend accros several SIRs.
> What I normally do is use smrby.ado because it includes a test for
> trend and heterogeneity. Alternatively, you might want to model the
> SIRs by using a GLM model with a Poisson error structure and then fit
> the factor of interest as a consecutive non-negative integer variable.
> Make sure you collapse your data before you model it.
>
> .collapse (sum) _d E pyrs, by(timeperiod)
> .xi, noomit:glm _d i.timeperiod if E!=0,fam(pois) lnoffset(E) eform noconstant
>
> gives you the SIRs
>
> .xi, noomit:glm _d timeperiod if E!=0,fam(pois) lnoffset(E) eform noconstant
>
> gives you the p-value for linear trend
>
> _d is the numner of events, E the number of expected. The p-value for
> timeperiod should give you the test for linear trend accross the
> groups.
>
>
> Hope it helps
>
> Raoul Reulen
> Cancer Research UK Graduate Training Fellow
>
>
>
>
>
> On 17/10/2007, roland andersson <[email protected]> wrote:
> > I have used strate.ado to calculate standardised incidence ratios with
> > standardisation for age, sex and timepriod. I want to make inferences
> > on the development of the SIRs over three timeperiods. Can you help me
> > with instruction how to do this?
> > *
> > * For searches and help try:
> > * http://www.stata.com/support/faqs/res/findit.html
> > * http://www.stata.com/support/statalist/faq
> > * http://www.ats.ucla.edu/stat/stata/
> >
>
>
> --
> -------------------------------------------------------
> Raoul C. Reulen
> Cancer Research UK Training Fellow
>
--
-------------------------------------------------------
Raoul C. Reulen
Cancer Research UK Training Fellow
*
* For searches and help try:
* http://www.stata.com/support/faqs/res/findit.html
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/
