TR available: Polychotomous classification.

[Jerome H. Friedman]

                  *** Technical Report available ***


                          ANOTHER APPROACH TO
                      POLYCHOTOMOUS CLASSIFICATION

                          Jerome H. Friedman
                          Stanford University
                        (jhf at stat.stanford.edu)

                               ABSTRACT

An alternative solution to the K - class (K > 2 - polychotomous) classific-
ation problem is proposed. It is a simple extension of K = 2 (dichotomous)
classification in that a separate two-class decision boundary is
independently constructed between every pair of the K classes. Each of these
boundaries is then used to assign an unknown observation to one of
its two respective classes. The individual class that receives the most
such assignments over these K(K-1)/2 decisions is taken as the predicted
class for the observation. Motivation for this approach is provided along
with discussion as to those situations where it might be expected to do
better than more traditional methods. Examples are presented illustrating
that substantial gains in accuracy can sometimes be achieved.

Available by ftp from:
"ftp://stat.stanford.edu/pub/friedman/poly.ps.Z"

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