[R-sig-ME] error message in glmmADMB

[Ben Bolker]

Marcela Rodriguero <rodriguero at ...> writes:

> 
> Dear list members,
> 
> I am trying to fit a glmmADMB model on my data, but altough I tried to fix
> it after reading many tutorials and forums, I couldn't do it.
> My response variable is the clutch size of females treated with an
> antibiotic or untreated (control females), and I took data over many days.
> Because lots of females put 0 eggs, I chose negative binomial over poisson
> family.

  OK.  (You might want to try zero-inflated variants as well.)

> The model looks like this:
> 
> model A= glmmadmb(count~treatment+(time|female),
> family="nbinom",data=table1)
> 
> This is the error message:
> Parameters were estimated, but not standard errors were not:
>  the most likely
> problem is that the curvature at MLE was zero or negative
> Error in glmmadmb(count ~ treatment + (time | female), family =
> "nbinom",data=table1) : 
>   The function maximizer failed (couldn't find STD file) Troubleshooting
> steps include (1) run with 'save.dir' set and inspect output files; (2)
> change run parameters: see '?admbControl'
> In addition: Warning message:
> running command 'C:\Windows\system32\cmd.exe /c
> -maxfn 500 -maxph 5 -noinit -shess' had status 1 
> 
> "Count" is the clutch size, my response variable, 'treatment' is a fixed
> effect, because I want to distinguish between clutch size of treated vs.
> untreated females, and "time" and "female" are random effects
>  because of the
> pseudorreplicate (i.e. random effects as nuisance).

   Hard to say without seeing your data.  How big is your data set
(how many females, how many per treatment, approximately how many
measurements per female?)  Did you try a simpler model such
as ~treatment+(1|female) ?  Did you try out the trouble-shooting
suggestions listed in ?admbControl?  (Other standard troubleshooting
suggestions such as centering and scaling your data may be less
relevant since your design looks pretty simple.  However, if the
minimum value of your time variable is far from zero, you might want
to subtract the minimum or center the time variable)

  Ben Bolker