[R-lang] Re: Why did I get different results when using different versions of lmer() ?

[Xiao He]

I have an additional question about lmer(). Sometimes I would get error
messages like this when running the earlier version of lmer():

____________
Warning messages:
1: In .local(x, ..., value) :
  Estimated variance-covariance for factor ‘Subject’ is singular

2: In .local(x, ..., value) :
  nlminb returned message false convergence (8)
_______________

>From what I've read, these errors are due to the fact that my model is too
complex for the data I have. What is interesting however is the fact that
these errors are rarer when I run the same data using the same models in the
latest version of lmer(). I wonder if anyone knows what is going on here....
Thanks again!


Best,
Xiao H.


On Sat, Jun 19, 2010 at 7:39 PM, Xiao He <praguewatermelon@gmail.com> wrote:

> Dear R-lang users,
>
> I recently started using lmer() and the languageR package. Because the
> latest version of lme4 package does not support MCMC sampling (error
> message: MCMC sampling is *not* yet implemented in lme4_0.999375-27), so I
> cannot use pvals.fnc() to obtain p-values. As a result, I decided to go
> back to an older version of lme4() that does support MCMC sampling. However,
> I've noticed when I tried to ran the exact data set on the two versions of
> lme4 packages, the results, such as t-values, SE, coefficients, I got from
> the two versions of lmer() were different. I wonder if I should be concerned
> about it. Thank you guys in advance
>
>
> Best,
> Xiao H.
>
>
>
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