Speaking with a Commonality Language

In recent years, the U.S. Army has become increasingly interested in “commonality” — the sharing of common parts across different entities. Unfortunately, commonality is poorly defined and conceptualized, which can contribute to confused discussion and poor decisionmaking. This report offers a new, more rigorous lexicon. It identifies nine concepts that are often conflated with commonality and discretely defines and conceptualizes them using examples for each concept. It is motivated by the reported costs arising from a lack of clear definitions during recent Army acquisition processes and by cases in which unclear definitions of commonality have led to significant problems. Commonality offers advantages and disadvantages. It can increase operational and logistical flexibility: If the same component can be replaced on multiple systems, the logistical burden decreases, and a common major component suggests common operational performance, helping different systems work together. Such components may also reduce development and procurement costs. However, commonality can decrease design freedom and operational flexibility. Moreover, the acquisition of common components across multiple systems might impose extra development or procurement burdens that outweigh the actual benefits. The Army needs to understand the benefits, burdens, and operations risks of commonality so that it can determine how much commonality should be sought.