Satomi Yamamoto <[email protected]> asks:
> Could I use the xtmixed command to run a null model? I used the pig.dta
> data (http://www.stata-press.com/data/r10/pig.dta) and run
> xtmixed weight||id:, var
> But, I was not able to converge the data:
[...]
> Is there another way of running the intercept only model in Stata? Or, did
> I forget to include options in xtmixed? It would be great if somebody could
> help me wit this.
There is nothing that states you can't fit a null model with -xtmixed-, and
the syntax you use is the correct one. It is just that in your particular
case -xtmixed- failed to converge, most likely because of a near-zero variance
component at the -id- level.
. sysuse auto, clear
. xtmixed mpg || rep78:
does converge. In fact, you can even be more "null" and do
. xtmixed mpg
or if you want to get really crazy
. xtmixed mpg, nocons
--Bobby
[email protected]
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