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Hello, has someone written by chance a function to extract the variance-covariance matrix from a lmer-object? I've noticed the VarCorr function, but it gives unhandy output. Regards, Roel de Jong

Hello, I'm running a simulation study of a multilevel model with binary response using the binomial probit link. It is a random intercept and random slope model. GLMMPQL and lmer fail to converge on a *significant* portion of the...

Hello, how do I obtain standard errors of variances and covariances of the random effects with LME comparable to those of for example MlWin? I know you shouldn't use them because the distribution of the estimator isn't symmetric...

Formulated more directly, are there plans for the implementation of the crude but more robust Marginal Quasi Likelihood estimation in for example LME? Regards, Roel de Jong Roel de Jong wrote: > Hello, > > I'm running a simulation study of a...

Hi, it is impossible to plot a subset of the variables at the moment, but we could add it. p.s. The latest version of mice is v1.14, which can be downloaded from CRAN. Roel de Jong. Leo G...

One thing I forgot to mention: the data was generated and fitted with the binomial probit (not logit) link Roel de Jong Roel de Jong wrote: > Dear professor Bates, > > thank you for your reaction. To make sure that no errors...

Of course it is generally possible to generate datasets for a perfectly well-defined model that are hard to fit, but in this particular case I feel it should be possible. In my observations, glmm.admb is far more numerically...

Dear professor Bates, thank you for your reaction. To make sure that no errors occur in the data generation process I used the elegant function you so neatly provided to generate a couple of datasets under the model specification specified...

Well I finally figured it out. If you use the delta method with transformations exp(x) for the standard deviations and ((exp(y)-1)/(exp(y)+1) for the correlation elements of the apVar structure, which is btw *not* the...

Dear R-users, because lme(r) & glmmpql, which are based on Penalized Quasi Likelihood, are not very robust with Bernoulli responses, I wanted to test glmmADMB. I run the following simulation study: 500 samples are drawn with the model specification...

Well, the dataset which I send in my previous message did without any doubt come from a multilevel model (generated and fitted under the binomial probit link), and gave the earlier posted error message while fitting it with the latest...

try MICE package :) regards, Roel de Jong (Ted Harding) wrote: > Folks, > > Leo G??rther and I have been privately discussing the > problems with imputation using NORM which he originally > described on 9 November. Essentially, he observed that > many of the...

I recently took Dave Fournier up on his offer to evaluate his AD Model builder package (http://otter-rsch.com/admodel.html) when fitting a GLMM under the binomial probit link. I conducted a simulation study in which I drawed...

The word unacceptable was maybe poorly chosen, but I meant it was unacceptable for my purposes that a lot of samples needed to be discarded. Further, I don't need to give code, data, or other reasons why the model...