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Error: cannot use PQL when using lmer

4 messages · hpdutra at yahoo.com, Ben Bolker, hpdutra +1 more

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y
  n   y 
 43 177
trt
y   placebo drug drug+
  0      12   18    13
  1      84   44    49
Error in match.arg(method, c("Laplace", "AGQ")) : 
  'arg' should be one of ?Laplace?, ?AGQ?
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<hpdutra <at> yahoo.com> writes:
What is your question?
  Doug Bates warned a few weeks ago that the newer version
of lmer would no longer use PQL for GLMMs (he found that
it was unreliable, even as a starting method for Laplace fits).
I think you can still get the older version if you want
it, or you can use glmmPQL from the MASS package (glmmPQL
has some advantages anyway).
   It might be better to forward further discussion to
r-sig-mixed.

   Ben Bolker
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In fact I am using  Crawley example to fit my data. 
I am running a lmer analysis for binary longitudinal (repeated measures)
data.
Basically, I have 12 plots, divided in 3 blocks, each block contain 4 plots.
Plots were manipulate for fruits (F) and vegetation (V) that were either
intact(I)  or removed(R). Thus, the treatments are 
FIVI
FIVR
FRVI
FRVR
Within each plot I had 16 track plates. Track plates were checked monthly
for presence or absence of paw prints. 
I am trying to fit lmer model 
track~fruit*vegetation*time*block in which fruit vegetation time are fixed
effects and time is repeated measures and block is a random effect
here is my code
Generalized linear mixed model fit by the Laplace approximation 
Formula: track ~ veget * fruit * time * (time | plate) * (1 | block) 
   AIC   BIC logLik deviance
 933.9 994.5 -454.9    909.9
Random effects:
 Groups Name        Variance Std.Dev. Corr   
 plate  (Intercept) 0.226747 0.47618         
        time        0.054497 0.23345  -1.000 
 block  (Intercept) 0.615283 0.78440         
Number of obs: 1152, groups: plate, 192; block, 3

Fixed effects:
                                        Estimate        Std. Error   z value  
Pr(>|z|)   
(Intercept)                             -1.68645    0.58718     -2.8721 
0.00408 **
vegetremoved                         -1.39291    0.57742     -2.4123 
0.01585 * 
fruitremoved                           -0.54486    0.53765     -1.0134 
0.31086   
time                                      -0.02091    0.10118     -0.2067 
0.83626   
vegetremoved:fruitremoved        0.75130    0.86342  0.8701  0.38422   
vegetremoved:time                   0.38229    0.14695  2.6014  0.00928 **
fruitremoved:time                     0.17012    0.14227  1.1958  0.23178   
vegetremoved:fruitremoved:time -0.47526    0.22134 -2.1473  0.03177 * 

According to Crawley PQL is better for fitting binary data like this. So
should I just stick Laplace or try to get the old Lme4? Also, if there is an
interaction of vegetation vs fruit vs time, how can I know which months
fruit had a significant effect?

 

=============================
Ben Bolker wrote:

  
    
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Hi hpdutra,
I do not know what section of which Crawley book you are referring  
to, but I assume that Crawley's point is to use a binomial error  
distribution (logistic regression) rather than a normal model. It is  
generally thought that LaPlace methods are more accurate than PQL  
methods.
Hank
On Jul 6, 2008, at 2:55 AM, hpdutra wrote: