The Comprehensive Program for Socialist Economic Integration was set up in 1971, laying the guidelines for Comecon activity until 1990. The distinction between "market" relations and "planned" relations, made in the discussions within Comecon before the adoption of the 1971 Comprehensive Program, is still a useful approach to understanding Comecon activities. Comecon remained in fact a mixed system, combining elements of both plan and market economies. Although official rhetoric emphasized regional planning, it must be remembered that intra-Comecon relations continued to be conducted among national entities not governed by any supranational authority. They thus interacted on a decentralized basis according to terms negotiated in bilateral and multilateral agreements on trade and co-operation.