search for: safeprediction

Executive Summary: This only concerns predict() at new points when the formula contained things like poly() or ns() {in the RHS}. Because I hadn't have time to fix this yet, I submit it. [R version 1.5.1 and at least 1.4.1, probably all versions at all:] For these, R 1.5.x does not differ from 1.4.1 : Inspite of R 1.5.0's "NEWS" entry and the ?Safepredict help page,

Are there any general guidelines for writing functions that appear in model formulas for functions like lm()/glm()? The ones I can think of are ns()/bs() in `splines' and s() in `mgcv'. It seems that ns()/bs() basically create matrix with a number of attributes and a class, while s() returns a list of parameters. It seems that gam() in `mgcv' has its own way of dealing with

I am fitting a regression model with a bs term and then making predictions based on the model. According to some info on the internet at http://www.stat.auckland.ac.nz/~yee/smartpred/DummiesGuide.txt there are some problems with using predict.lm when you have a model with terms such as bs,ns,or poly. However when I used one of the examples they said would illustrate the problems I get virtually