Offset for spautolm function in Spatialreg package
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 at 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 at 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 at umn.edu,;+1 848-480-9250; linkedin.com/in/kaushi-kanankege <https://www.linkedin.com/in/kaushi-kanankege> [[alternative HTML version deleted]]