Although considered a helpful tool a decade ago, the specification of the development problem in terms of one aim/one nation/one actor avoids the issues and is unrealistic. This paper reports on two models which introduce explicitly social groups as independent actors. The first model examines the formation of income, employment, human resources and satisfaction of basic needs for various social groups. The second model examines the distribution of wealth in a framework which assigns a more dominant role to a particular group on other groups. Applications of the models to four countries are briefly reviewed.