On 24 Mar 2023, at 09.12, Thierry Onkelinx via R-sig-mixed-models <r-sig-mixed-models at r-project.org> wrote:
Dear Robert,
IMHO you should remove the cbind(0, 0) before fitting the model. There is
no reason to keep them in the dataset.
Best regards,
ir. Thierry Onkelinx
Statisticus / Statistician
Vlaamse Overheid / Government of Flanders
INSTITUUT VOOR NATUUR- EN BOSONDERZOEK / RESEARCH INSTITUTE FOR NATURE AND
FOREST
Team Biometrie & Kwaliteitszorg / Team Biometrics & Quality Assurance
thierry.onkelinx at inbo.be
Havenlaan 88 bus 73, 1000 Brussel
www.inbo.be
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Op vr 24 mrt 2023 om 02:39 schreef rtfiner <rtfiner at gmail.com>:
I have a question about how glmmtmb handles proportion data for the
purposes of a binomial glmm.
I combined my success and failure count data into a matrix using cbind(),
and used that as my response in my binomial glmm using glmmtmb.
However, despite there being a few instances of zero counts in both columns
and therefore an undefined proportion, the model doesn't seem to drop these
rows from my data set.
I don't get any errors or warnings when running the model, but I worry my
results might be biased because of this.
My question is: Is glmmtmb doing something like adding a tiny amount to
each value of my response in order to avoid dealing with undefined
proportion data?
Thank you for your help,
Robert
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