This study of the British Bicycle and Domestic Radio Receiver industries produced a model of invention/product design having the following features: Invention depended mainly on the combined effect of three factors, each with changing significance over a three-stage life cycle.
Technology Factor: Induced a cumulative sequence of inventions to improve product performance, of various origins (ideas, problems, techno-transfers or science). This factor most important in the first Incubation stage, of equal importance in second Early Growth stage and of incremental importance in final Mature stage.
Economic Factor: Induced invention to suit market, mainly for cheaper, lower performance products but also for superlative models. This factor inoperative at Incubation stage, very important at Early Growth stage and important at Mature stage.
Consumer Factor: Induced invention to make products more appealing to consumer; for simpler/automatic operation, greater reliability, accessories and new uses. This factor inoperative at Incubation stage, important at Early Growth stage and supremely important at Mature stage.
Product life-cycle pattern a sequence of new models subsequently improved until an basic satisfactory design achieved, later incrementally improved. Empirical invention often systematic and as important as scientific invention; science often used to define design problem. Peak invention in Early Growth stage to explore all technical possibilities, design trade-offs and for market share.
Invention and Demand: No direct and proportional relationship. Initial demand due to novelty appeal of function, subsequent rapid increased demand due to better technical product performance, lower product prices and increased income-related purchasing power. After market saturation demand declined despite better, sometimes radical, designs; as consumers sought other new products
