A review of literature in economics and marketing suggests that since Raymond Vernon published his article "International Investment and International Trade in the Product Cycle" in 1966,1 there has been a simultaneous development of literature pertaining to the 'product cycle' in marketing. There are differences between Vernon's concept of the product cycle and marketers' perception of the product life cycle. However, when one reviews publications in areas where these disciplines tend to overlap, particularly in international marketing and international business, both of these terms tend to fuse together and be used almost interchangeably.
While discussing Vernon's model, Louis T. Wells, Jr. states that "the model claims that many products go through a trade cycle, during which the United States is initially an exporter, then loses its export markets and may finally become an importer of the product"2. Warren Keegan, a marketing scholar, on the other hand, refers to the International Product Life Cycle in the following manner: "The International Product Life Cycle model suggests that many products go through a cycle during which high income, mass consumption countries are initially exporters, then lose their export markets, and finally become importers of the product."3 These are clear instances where trade cycle and product life cycle have been defined almost identically in the international context.
There could be several possible explanations for the interchangeable use of the product cycle and product life cycle concepts. One explanation is that the product cycle, developed by economists as part of the international framework, was initially unknown to marketers when they developed the product life cycle concept.4 Another possibility is that marketers, in order to extend the product life cycle concept to international markets, borrowed the product cycle concept from economists who employed the concept to explain patterns of international