[R-sig-Geo] Offset for spautolm function in Spatialreg package

[Kaushi Kanankege]

Hi Dr. Bivand,
Thank you for the reply. That makes sense. I was hoping there'd be a way to
set an offset like in glm function even though it's Gaussian dependent.
But, of course as you've brought up I'm running a Poisson model here.
I ended up using CARBayes package for the purpose eventually. Thank you
very much again for the prompt reply and the suggestions.

Have a good day!
Best,
Kaushi



On Mon, Nov 23, 2020 at 5:30 AM Roger Bivand <Roger.Bivand using nhh.no> wrote:

> On Sun, 22 Nov 2020, Kaushi Kanankege via R-sig-Geo wrote:
>
> > Dear members of the R-sig-Geo,
> > Is there a way to set an 'offset' when running a Poisson regression using
> > the spautolm function offered in the Spatialreg package?
>
> The spautolm function in spatialreg only supports Gaussian dependent
> variables. Perhaps the family= argument misled you to think otherwise, it
> takes the values c("SAR", "CAR, "SMA"), not distribution names. It was
> written as its help page describes to support the spatial regression
> chapter in Waller & Gotway (2004).
>
> For Poisson CAR, see the hglm package, CARBayes, INLA, R2BayesX and many
> others (also mgcv gam() with an "mrf" smooth).
>
> Hope this clarifies,
>
> Roger
>
> >
> > I have count data of disease at administrative levels and I am trying to
> > use CAR model to account for the spatial dependence between the admin
> > levels. I would appreciate suggestions of setting the offset (the log of
> a
> > total number of animals in each admin level) or ways to work around this
> > using spautolm function.
> >
> > Thank you very much.
> >
> > Kaushi
> >
> > Further details below:
> >
> > # Unit of analysis is ‘Districts’ i.e. administrative divisions
> >
> > # Count_disease = number of animals with the disease
> >
> > # Var 1 and 2 are selected independent variables
> >
> > # We have the count of animals per each district and I am trying to set
> > this as the ‘offset’
> >
> >
> >
> > # The same model was run as a zero inflated Poisson regression using the
> > following
> >
> > offset = log(Ani_pop)
> >
> > ZIP.D <- zeroinfl(formula_Red, data = Data, dist = "poisson", EM = TRUE,
> > link = "logit", offset = offset)
> >
> >
> >
> > #Formula
> >
> > formula <-  Count_disease ~  Variable 1 + Variable2
> >
> > # CAR fit
> >
> > CAR.D <- spautolm(formula_Red, data= Thai.D.shp2, listw=ThaiD.listw,
> > family="CAR",zero.policy = TRUE, method="eigen")
> >
> >
> >
> > How to set the offset?
> >
> > Or suggestions to work around this?
> >
> >
> >
> >
>
> --
> Roger Bivand
> Department of Economics, Norwegian School of Economics,
> Helleveien 30, N-5045 Bergen, Norway.
> voice: +47 55 95 93 55; e-mail: Roger.Bivand using nhh.no
> https://orcid.org/0000-0003-2392-6140
> https://scholar.google.no/citations?user=AWeghB0AAAAJ&hl=en



-- 

Kaushi Kanankege (DVM, MS, PhD)
Postdoctoral Associate
Center for Animal Health and Food Safety
University of Minnesota Twin Cities
kanan009 using umn.edu,;+1 848-480-9250;
linkedin.com/in/kaushi-kanankege
<https://www.linkedin.com/in/kaushi-kanankege>

	[[alternative HTML version deleted]]