A Formalization of the ISO/IEC 15504: Enabling Automatic Inference of Capability Levels

This paper presents a formalization that captures definitions of a number of concepts of ISO/IEC 15504 and relations among the concepts. The formalization is expressed in a formal language, OWL. The two main objectives for this formalization was to be consistent with the ISO/IEC 15504-5 process assessment model and to be effective, i.e., to allow for an automatic determination of a process capability level based upon data about the process attributes and ratings. The formalization is presented in a number of levels, from more general concepts to more specific. To assess the validity of the formalization, a number of test cases for the scenario of automatic determination of the capability levels were developed. A set of OWL reasoners were then used to derive the capability levels for the acquisition process group. While the test results were all positive, the real value of this formalization comes from the fact that it faithfully captured the main aspects of ISO/IEC 15504, a well established and accepted model for the assessment of processes capability levels, and that an inference engine was able to support the assessment of processes capability levels of an organization.