[R] variance explained by each term in a GAM

2011-03-10 Thread Pierre Kleiber
Picking up an ancient thread (from Oct 2007), I have a somewhat more complex problem than given in Simon Wood's example below. My full model has more than two smooths as well as factor variables as in this simplified example: b <- gam(y~fv1+s(x1)+s(x2)+s(x3)) Judging from Simon's example, my g

Re: [R] variance explained by each term in a GAM

2007-10-12 Thread Julian Burgos
Dear Prof. Wood, Just another quick question. I am doing model selection following Wood and Augustin (2002). One of the criteria for retaining a term is to see if removing it causes an increase in the GCV score. When doing this, do I also need to fix the smooth parameters? Thanks, Julian B

Re: [R] variance explained by each term in a GAM

2007-10-09 Thread Julian Burgos
Thanks again for your answer, prof. Wood. And my apologies for the list for my repeated message from yesterday. Still trying to figure out what happened with my email software. Julian Simon Wood wrote: > I think that your approach is reasonable, except that you should use the same > smoothing

Re: [R] variance explained by each term in a GAM

2007-10-09 Thread Simon Wood
I think that your approach is reasonable, except that you should use the same smoothing parameters throughout. i.e the reduced models should use the same smoothing parameters as the full model. Otherwise you get in trouble if x1 and x2 are correlated, since the smoothing parameters will then ten

[R] variance explained by each term in a GAM

2007-10-08 Thread Julian M Burgos
Hello fellow R's, I do apologize if this is a basic question. I'm doing some GAMs using the mgcv package, and I am wondering what is the most appropriate way to determine how much of the variability in the dependent variable is explained by each term in the model. The information provided by sum

[R] variance explained by each term in a GAM

2007-10-08 Thread Julian M Burgos
Hello fellow R's, I do apologize if this is a basic question. I'm doing some GAMs using the mgcv package, and I am wondering what is the most appropriate way to determine how much of the variability in the dependent variable is explained by each term in the model. The information provided by