[Retrospective analysis of drug projection using correlative technics].

The problem of choosing substituents to allow correct correlative analysis according to the "Hausch Approach" is discussed. The problem of colinearity among parameters is considered in a case study on 296 anilides which inhibit the Hill reaction. The difficulty in of determining whether, pi or MR is the important variable in changes in activity is shown. "Cluster analysis" is discussed and proposed as a rational method for the selection of substituents to be introduced into biologically active structure in order to explore the scope of each defined physico-chemical parameter. An example of the use of this method conerning auxin activity of 1- and 2-benzotriazole derivatives is given.