Many companies approach product development as if it were manufacturing, trying to control costs and improve quality by applying zero-defect, efficiency-focused techniques. While this tactic can boost the performance of factories, it generally backfires with product development. The process of designing products is profoundly different from the process of making them, and the failure of executives to appreciate the differences leads to several fallacies that actually hurt product-development efforts. In this article, the authors, an HBS professor and a consultant, expose these misperceptions and others. They look at six dangerous myths: 1) High utilization of resources will make the department more efficient; 2) Processing work in large batches will be more economical; 3) Teams need to faithfully follow their development plan, minimizing any deviations from it; 4) The sooner a project is started, the sooner it will be finished; 5) The more features a product has, the better customers will like it; and 6) Projects will be more successful if teams "get them right the first time." The authors explain the negative effects these "principles" have when applied to product development, offer practical guidelines on overcoming them, and walk readers through a visual tool that will help them keep projects on track.

As product complexity and the rate of market change have dramatically increased over the last years, firms find it increasingly difficult to forecast product requirements in their development processes. This article redefines the problem from one of improving forecasting to one of increasing product development agility and thus reducing the need for accurate long-term forecasts. It introduces the notion of development flexibility, shows how it can be measured, and presents results from a large empirical study on integrated systems development, which found that projects using flexible technologies outperformed projects using inflexible technologies by a factor of 2.2 (in person-months). Finally, the article proposes three major strategies for introducing flexibility into organizations. These strategies can help firms increase their agility and position themselves to succeed in accelerating and more turbulent markets.