Pattern recognition for the study of structure—activity relationships: Uses of the adaptive least-squares method and linear discriminant analysis

The adaptive least-squares method (ALS) and linear discriminant analysis (LDA) were applied to structure—activity correlation studies including the antitumor activity of mitomycin derivatives, the relative binding affinities of 100 steroids for five receptors, assignment of the pharmacological category of 80 diarylmethane-derived drugs, and discrimination of the adverse reaction of 98 miscellaneous drugs that may induce liver and/or blood diseases. Generally, more satisfactory results were obtained by the use of ALS than by LDA, both in recognition and in leave-one-out predictions. However, LDA was not always inferior to ALS in the applications, especially those related to classification of independent categories.