[R] GAM model output error(?)

[Simon Wood]

Trevor,

It looks like you've added a parametric COR.YEARLY.MEAN in addition to 
your s(cxe,cyn,by=COR.YEARLY.MEAN) term. Because the latter includes a 
linear effect of COR.YEARLY.MEAN, then the parametric COR.YEARLY.MEAN 
will not be identifiable, so gam has dropped it.

I guess from the scale parameter your data are, if anything, 
under-dispersed relative to Poisson, but perhaps Poisson would have been 
ok too.

Could you give a bit more detail on 'NB just wouldn't work' please? What 
actually happened? (It's new functionality, so having reports when stuff 
goes wrong is useful).

best,
Simon

On 16/07/14 20:25, Trevor Davies wrote:
> I have run a quasipoisson spatial model via GAM (NB just wouldn't work) and
> I am getting the following output of one of my parameters
> (COR.YEARLY.MEAN).  Does this suggest an error in the model fit? The model
> seems to have converged.  Apologies for the lack of reproducible example
> but it didn't really seem warranted in this case.  Thank you for the
> assistance.
> Trevor
>
> Parametric coefficients:
>                  Estimate Std. Error t value Pr(>|t|)
> (Intercept)      -3.7084     0.2185  -16.97   <2e-16 ***
> COR.YEARLY.MEAN   0.0000     0.0000      NA       NA
> ---
>
> Approximate significance of smooth terms:
>                                             edf Ref.df       F  p-value
> s(PRED_cBOTTOM_TEMPERATURE.std)          5.008  6.045  24.871  < 2e-16 ***
> s(cxe,cyn)                              28.999 29.000  13.951  < 2e-16 ***
> s(cDMAX.std)                             3.830  4.761 243.895  < 2e-16 ***
> s(cxe,cyn):male.allyear.intensity.std    8.053  9.923   4.486  2.8e-06 ***
> s(cxe,cyn):female.allyear.intensity.std  3.733  4.334   5.478 0.000149 ***
> s(cxe,cyn):COR.YEARLY.MEAN              28.979 29.886  28.502  < 2e-16 ***
> s(cxe,cyn):cFISHING_INTENSITY.std        5.592  6.464  24.330  < 2e-16 ***
> -
> Rank: 1/169
> R-sq.(adj) =  0.697   Deviance explained = 64.1%
> GCV = 0.70372  Scale est. = 0.69061   n = 4575
>
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-- 
Simon Wood, Mathematical Science, University of Bath BA2 7AY UK
+44 (0)1225 386603               http://people.bath.ac.uk/sw283