Chapter 4 The Model Object

• Saving the call is discouraged. If it must be saved, it should be checked for size. In cases where the function is invoked by do.call("foo", bar), the data set may be embedded in the argument list bar.

• Unless explicitly required by the model, the training set should not be embedded in the model object (exceptions being models such as k-nearest neighbors).

• Retain the minimally sufficient objects in the model object. {note}

• When providing a convenience interface that allows fitting more than one type of model, the resulting model objects should have different classes for each type of model. {note}