[R-sig-ME] GLMM hurdle model for continuous data -Truncated negative binomial family in glmmTMB?

[Ben Bolker]

   Responded on CV.  Short answer: glmmTMB does have a 'ziGamma' family 
that should allow a zero-hurdle Gamma model ...

On 8/1/20 2:09 PM, Alessandra Bielli wrote:
> Dear List
>
> I have posted the question below on Cross Validated as well, where you can
> find the image of the diagnostics plots.
> https://stats.stackexchange.com/questions/481109/truncated-negative-binomial-hurdle-model-for-continuous-data-glmmtmb
>
>
>
> I am running a hurdle model using the glmmTMB function. My dependent
> variable is continuous and >= 0. I was looking for a function that would
> allow me to model the binary response in a logistic regression (i.e the
> zero inflated model) and the non-zero response in a Gamma (log) regression
> (i.e the conditional model). However, the glmmTMB function does not allow
> to use the gamma family.
>
> I have two questions:
>
>     1.
>
>     is there a function that allows to run a GLMM with gamma family? I tried
>     to write my own code to have these two models but I am not sure about how
>     to predict and calculate CIs.
>     2.
>
>     Is it appropriate to use a truncated negative binomial family for the
>     conditional (non-zero values) model? I ran the model:
>
> hpm_nb <- glmmTMB(percapita_dia ~ Tipo_residuo + (1|Trip_ID),
> zi=~Tipo_residuo, all, family=truncated_nbinom2)
>
> The diagnostics plots look good and model predictions are reasonable. Is it
> still wrong to have a truncated negative binomial family?
>
> Thanks for your help,
>
> Alessandra
>
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>
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