-----Oorspronkelijk bericht-----
Van: r-sig-mixed-models-bounces at r-project.org [mailto:r-sig-mixed-models-
bounces at r-project.org] Namens Hans Ekbrand
Verzonden: vrijdag 1 juli 2011 12:26
Aan: r-sig-mixed-models at r-project.org
Onderwerp: Re: [R-sig-ME] Specifying a (simple?) two level model
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).