Robust Linear Discriminant Trees George H. John Computer Science Department Stanford University Stanford, CA 94305 gjohn@cs.Stanford.EDU We present a new method for the induction of classification trees with linear discriminants as the partitioning function at each internal node. This paper presents two main contributions: first, a novel objective function called soft entropy which is used to identify optimal coefficients for the linear discriminants , and second, a novel method for removing outliers called iterative re-filtering which boosts performance on many datasets. These two ideas are presented in the context of a single learning system called DT-SEPIR, which is compared with the CART and OC1 algorithms. Citation: George H. John. Robust linear discriminant trees. In D. Fisher and H. Lenz, editors, _Learning From Data: Artificial Intelligence and Statistics V_, Lecture Notes in Statistics, Chapter 36, pages 375--385. Springer-Verlag, New York, 1996.