Re: [R] GLM model vs. GAM model

2004-10-28 Thread Simon Wood
For GAMs fitted using mgcv::gam, I think that there's an argument that the most self consistent comparison would be based on the GCV/UBRE score for the models, since this has usually been used to select the degree of smoothness of the GAM model (you can fit the GLM using gam(), so this is avail

Re: [R] GLM model vs. GAM model

2004-10-26 Thread Prof Brian Ripley
R does not contain a gam() function. *Two* contributed packages, gam and mgcv, do. Please do as the posting guide asks and clarify what you are talking about here. Your penultimate para is not logical: the tests are _not_ based on maximum likelihood if ML fitting is not used. However, there ar

Re: [R] GLM model vs. GAM model

2004-10-26 Thread Thomas Lumley
On Tue, 26 Oct 2004, SUBIRANA CACHINERO, ISAAC wrote: I have a question about how to compare a GLM with a GAM model using anova function. You don't say what gam() function you are using. There are at least two out there and they work in quite different ways. A GLM is performed for example: model1

[R] GLM model vs. GAM model

2004-10-26 Thread SUBIRANA CACHINERO, ISAAC
I have a question about how to compare a GLM with a GAM model using anova function. A GLM is performed for example: model1 <-glm(formula = exitus ~ age+gender+diabetes, family = "binomial", na.action = na.exclude) A second nested model could be: model2 <-glm(formula = exitus ~ age+gender, fami