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


From   Christian Weiß <C.Weiss@plusser-portal.de>
To   "statalist@hsphsun2.harvard.edu" <statalist@hsphsun2.harvard.edu>
Subject   AW: st: 3 Level - LMM - Number of clusters?
Date   Wed, 25 Jun 2008 11:21:20 +0200

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
-----Ursprüngliche 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 Weiß 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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