Re: st: robust cluster in GLM

[Steven Samuels <sjhsamuels@earthlink.net>]

Leny, that's not exactly the information I asked for,  but there is  
probably nothing wrong with your result.  If you have at least 2 time  
points per case, then a line can be estimated within each.  Therefore  
all 80 cases will be utilized in the analysis.

-Steve

On Sep 16, 2008, at 5:12 PM, Leny Mathew wrote:


> Sorry about that Steve, SE of the coefficient. Time is in weeks and is
> used as continuous in the model. The average at T1 is 10 weeks, T2 is
> 20 weeks and T3 is 29.7 weeks.
>
> Leny
>
> On Tue, Sep 16, 2008 at 4:27 PM, Steven Samuels
> <sjhsamuels@earthlink.net> wrote:
> > -
> >
> > Leny, "standard error" of what?  Please follow the Statalist FAQ  
> > (section
> > 3.3) and "Say exactly what you typed and exactly what Stata typed  
> > (or did)
> > in response. N.B. exactly!"  Are the time-points equally spaced?   
> > If so, and
> > you are estimating the slope, then the middle time point would be  
> > ignored.
> >
> > -Steve
> >
> >
> > On Sep 16, 2008, at 3:46 PM, Leny Mathew wrote:
> >
> >
> > > Dear Statalisters,
> > >                          I'm using a GLM model with robust cluster
> > > option to model longitudinal data across three time points. I  
> > > have the
> > > dependent variable on 80 cases at T1 and T2, but have only 77 at the
> > > third time point. When I run the model the number of observations is
> > > 237, but it says that the standard error is adjusted for 80  
> > > clusters.
> > > Why would this be the case? How does stata take the missing info for
> > > the 3 people at T3 into consideration when it calculates the
> > > parameters and SE?
> > >
> > > Thanks in advance for any suggestions,
> > >
> > > Leny
> > > *
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