[R-sig-ME] lmer vs glmmPQL

Ben Bolker bolker at ufl.edu
Wed Jun 24 14:15:51 CEST 2009

Federico Calboli wrote:
> On 23 Jun 2009, at 22:46, Ken Beath wrote:
>> This seems to results from the use of a t-test with few df in glmmPQL
>> and z in lmer. z seems fine to me. What is more of a problem is that
>> your random effects variance is effectively 0. There are only 3 blocks
>> so fitting a random effects model will be difficult and appears
>> unnecessary.
> That was a sample dataset so I could see what kind of data I had to  
> deal with, the 'real' hing should have a variance > 0 for the random  
> effect. My philosphycal issue was, given such a relatively  
> straightforward model, should I be more (glmmPQL) or less (lmer)  
> conservative?
> Best,
> Federico

  My take would be to pick lmer over glmmPQL every time, provided
it can handle your problem -- in general it should be more accurate.
Picking on the basis of more or less conservative for any given problem
feels biased.

  Ben Bolker

More information about the R-sig-mixed-models mailing list