Hi, Is there any way I can see how exactly the prediction equation is constructed in the example below? I'd like to be able to replicate the predictions from the fitted gam object as given by the predict.gam method in the package "mgcv". library(mgcv) data(trees) ct1 <- gam(Volume ~ s(Height) + s(Girth), family=Gamma(link=log), data=trees) summary(ct1) newdata <- cbind(Girth=mean(trees$Girth), Height=mean(trees$Height), Volume=mean(mean(trees$Volume))) pred <- predict(ct1,as.data.frame(newdata),type="response") pred Thanks in advance, Lars. [[alternative HTML version deleted]]