A commercial-off-the-shelf (COTS) component is an implementation of common functionality among family members, where an in-house component implements an organization-specific functionality. Typically, a COTS component has a producer and a set of potential consumers. Consumers evaluate COTS components thoroughly before they purchase, because these components are developed by third party producers and most consumers have ‘not-invented-here’ syndrome. Hence, evaluating the quality of COTS components becomes an important prerequisite to a successful component-based application development. In this paper, we identify the characteristics of COTS components, and derive a practical quality model for components, C-QM, which consists of quality factors, criteria and metrics. The top design goal of C-QM is set to provide a practically applicable comprehensive quality model which can be effectively applied in assessing the various quality aspects of COTS components. Key Words: Component-Based...