In developing a machine learner to classify sentences in plain text sources of scientific documents I have been using the caret package and following the procedures described in the vignettes. What I miss in the package -- but quite possibly I am overlooking it! -- is functions that allow me to estimate whether a model has too much variance or too much bias. In particular, I am looking for something that helps me compare the training and test errors as functions of training set size. Clearly, I can program something in R, but if there is already a function in some package to do that, I would prefer to use it, of course. Regards, Richard [[alternative HTML version deleted]]