A GENERALIZED FORM OF THE FISHER-PRY MODEL OF TECHNOLOGICAL SUBSTITUTION

In this paper we propose a possible generalization of the Fisher-Pry m odel of technology substitution by making the growth parameter time de pendent. The computation of time dependence of the growth parameter al lows us to measure departures from the Fisher-Pry description and sugg ests possibilities of making better forecasts. Three representative da ta sets have been analyzed to illustrate our arguments.