| Summary: | CHAID (Chi-squared Automatic Interaction Detection), proposed by Kass in 1980, is an
algorithm to detect, in automatic way, the interaction between two or more predictors and its
role in the expla
paradox is present. This is due to the fact that CHAID is a forward selection algorithm based
on the marginal counts rather than in considering the conditional independent. In other words,
CHAID uses marginal information by examination of the table of marginal totals formed by
summing over the remaining factors, but it is well known that collapsibility is not always licit.
This paper will propose alternative algorithms, they are Forward and Backward
algorithms based on entropy. The Forward algorithm is generated by procedure in which is
similar to the classic CHAID procedure, except that it uses the likelihood ratio to test for
independence and entropy to evaluate the changes. The Backward algorithm is started with the
full set of predictors and then continued with eliminating the predictors progressively. The
elimination procedure is based on conditional independence and the use of entropy to test it.
From both algorithms, the Backward is the suggested algorithm as alternative for CHAID
segmentation algorithm
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