Knowledge that Transforms

—Editorial by William J. Horvath, Mental Health Research Institute, University of Michigan —Letters to the Editor –“To the Editor” by Ray Radosevich, The University of Kansas, Thomas H. Naylor, Duke University –“To the Editor” by Harold Bierman, Jr. Cornell University.

—“The question-asking machine” The research director of a Mid-western ad agency once told me that the trouble with operations researchers was that they only made answer machines. He insisted that there was no significant value to him to get answers. Instead, he said, what he needed was a good question asking machine. —The mailbag –“To the Editor” (name withheld on request) –“To the Editor” by Robert J. Schreiber, Time, Inc., New York.

An erratum to Jen, Frank C., C. Carl Pegels, Terrence M. Dupuis. 1968. Optimal capacities of production facilities. Management Sci. 14(10) B-573–B-580.

—“The Markov visitation” (It often seems as if the basic tool of operations research in marketing is the Markov chain. There are few O.R. people who have looked into marketing who haven't attempted to apply the tool.) Researchers have also invented a variety of ways to deal with variable purchase intervals, some as simple as using two chains which interweave. One assesses whether a purchase will be made in the next time interval and the second deals with the brand choice. —The mailbag –“To the Editor” by R. A. Longman, Fullerton, California

—Editorial by Timothy W. Costello, Deputy Mayor—City Administrator, City of New York and Sheldon S. Zalkind, Professor of Psychology, Baruch School, City University of New York

—Editorial by Ivan M. Siroyezhin, Head, Laboratory of Mathematics in Economics, Leningrad University, Leningrad, U.S.S.R.