*I tried using 'update' which should (I believe) initialise at the simpler
model:

> f0128biu = update(f0128bi, . ~ . + (1|tree))
Error in model.frame.default(formula = fincr ~ icfac + (1 + gap) + (1 +  :
  invalid type (closure) for variable 'box'

Murray

PS  a bit more of the context below:


f0128b = lmer(fincr ~ icfac + (1|gap) + (1|box), family = binomial)
summary(f0128b)
f0128bi = lmer(fincr ~ icfac + (1|gap) + (1|box)+ (1|gap:box), family =
binomial)
summary(f0128bi)
anova(f0128b,f0128bi)
f0128bit = lmer(fincr ~ icfac + (1|gap) + (1|box)+ (1|gap:box) + (1|tree),
family = binomial)
summary(f0128bit)
anova(f0128bit,f0128bi)
f0128biu = update(f0128bi, . ~ . + (1|tree))
anova(f0128bi,f0128biu)

*
On 17 May 2012 12:22, David Duffy <David.Duffy@qimr.edu.au> wrote:

> On Thu, 17 May 2012, Murray Jorgensen wrote:
>
>  it is counterintuitive to me that adding a random effect to a GLMM should
>> lead to a drop in the likelihood of the fitted model
>>
>
>  f0128bit: fincr ~ icfac + (1 | gap) + (1 | box) + (1 | gap:box) + (1 |
>> f0128bit:     tree)
>>        Df    AIC    BIC  logLik Chisq Chi Df Pr(>Chisq)
>> f0128bi   7 615.73 655.48 -300.87
>> f0128bit  8 687.01 732.43 -335.51     0      1          1
>>
>
> It's not counterintuitive, it's wrong  ;)  So either N's are different or
> program got stuck.  Try fiddling with starting values.
>



-- 
Dr Murray Jorgensen      http://www.stats.waikato.ac.nz/Staff/maj.html
Department of Statistics, University of Waikato, Hamilton, New Zealand
Email: maj@waikato.ac.nz    majorgensen@ihug.co.nz      Fax 7 838 4155
Phone  +64 7 838 4773 wk    Home +64 7 825 0441   Mobile 021 0200 8350

	[[alternative HTML version deleted]]

