Re: AW: st: 3 Level - LMM - Number of clusters?

[Steven Samuels <sjhsamuels@earthlink.net>]

Christian,

Do simpler models work?

1. Ignore SIC and just do a nesting within country?
2. Ignore country and just nest in coarse and refined SIC groupings,  
coded to not repeat between countries).
3. Fit a fixed effect for country and a random effect for SIC, also  
coded not to repeat between counries?

What commands are you using?  What models and covariates?

Regards,

-Steve
On Jun 25, 2008, at 5:21 AM, Christian Wei� wrote:


> Dear Steven,
>
> It's almost as you described in "B".
>
> Firms are nested within in industries
> & Industries are nested within countries.
>
> You are definitely right that SIC codes are not country specific.  
> However, the data I am analyzing do take country differences of  
> industries into account, so there is no problem at this point.
>
> At this point, the key question is whether there might be a problem  
> with the number of clusters I am trying model. (2000 firms, 11  
> countries, 9 (or 69) industries).
>
> Best regards
> Christian
> -----Urspr�ngliche Nachricht-----
> Von: owner-statalist@hsphsun2.harvard.edu [mailto:owner- 
> statalist@hsphsun2.harvard.edu] Im Auftrag von Steven Samuels
> Gesendet: Mittwoch, 25. Juni 2008 03:41
> An: statalist@hsphsun2.harvard.edu
> Betreff: Re: st: 3 Level - LMM - Number of clusters?
>
> Do you mean:
> A
> 1. countries are nested within industries
> 2. firms are nested within countries?
>
> This doesn't seem right to m
> Or
> B
> 1. industries are nested within countries
> 2. firms are nested within industries.
>
> In fact, neither A nor B seems right to me, as SIC codes are not
> unique to countries nor countries to SIC codes.
>
>
> Please clarify the structure of your problem.
>
> -Steve
> On Jun 24, 2008, at 12:04 PM, Christian Wei� wrote:
>
>
> > Hello!
> >
> >  I am currently trying to bugfix a linear mix model. My sample
> > comprises about 2000 observations (firms) which are nested as  
> > follows:
> >
> > Level  1:  nested in 9 industries (1 Digit SIC Code) or(!)  68
> > industries (2 digit SIC code)
> > Level 2:   nested in  11 countries
> >
> > Most of the modeled effects will be random.
> >
> > Is it possible, that the number of industries /  countries causes
> > my model not to converge? (I somehow recall having read that about
> > 20 clusters should be used?)
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