[R-sig-ME] Specifying a (simple?) two level model

[Hans Ekbrand]

On Thu, Jun 30, 2011 at 08:41:09AM +0000, ONKELINX, Thierry wrote:
> Dear Hans,
> 
> I would rather fit (0 + cluster|country). 1 + cluster will use the first cluster as reference and then calculate the differences for the other clusters. Whereas 0+cluster will directly estimate the effect of each cluster. Therefore the variance-covariance matrix of the random effect will be easier to interpret.

I see. Thank you the help.

> However with 22 clusters, the variance-covariance matrix will be 22x22. Which is large and thus takes time to fit.
> 
> A second problem is that you have complete separation in your dataset: some clusters in some countries have only 0 or only 1. That creates numerical problems: logit(0) = -Inf and logit(1) = Inf

Interesting, perhaps it will work if I correct that (exclude some
contries, or merge some of smaller clusters).

BTW, how did you notice?