A metric for evaluating design commonality in product families

Many companies develop a market strategy built around a family of products. These companies regularly add new product variations to the family in orde r to meet changing market needs or to attract a broader customer base. Alth ough the core functionality remains essentially unchanged across the produc ts within a family, new functions. feature combinations and technologies ar e incorporated into each new: product. If allowed to grow unchecked, these component variations, commonly: referred to as ''complexity", can result in a loss of productivity or quality. The challenge lies in an effective mana gement of product variations in the design studio and on the manufacturing floor. The key is to minimize non-value added variations across models with in a product family without limiting customer choices. In this paper we dis cuss the factors that contribute to product complexity in general, and pres ent an objective measure, called the Product Line Commonality Index, to cap ture the level of component commonality in a product family. Through our Wa lkman case study, we present a simple yet powerful method of benchmarking p roduct families. This method gauges the family's ability to share parts eff ectively (modularity) and to reduce the total number of parts (multi-functi onality).