Notes and Insights is a forum for discussion and debate about current issues in the philosophy and application of the system dynamics approach, and a marketplace for the exchange of information about current research, policy issues and teaching experiences. Manuscripts treating material particularly suited to presentation in short form (less than 2,000 words) should be sent to Erich Zahn, Betriebswirtschaftlic hes Institut, Abt. IV, Universität Stuttgart, Keplerstr. 17, D-7000 Stuttgart 1, Germany or to Yaman Barlas, Dept. of Industrial Engineering, Bogazici University, 80815 Bebek, Istanbul, Turkey.