Ilja Heitlager, Tobias Kuipers, Joost Visser. A Practical Model for Measuring Maintainability. In Ricardo Jorge Machado, Fernando Brito e Abreu, Paulo Rupino da Cunha, editors, Quality of Information and Communications Technology, 6th International Conference on the Quality of Information and Communications Technology, QUATIC 2007, Lisbon, Portugal, September 12-14, 2007, Proceedings. pages 30-39, IEEE Computer Society, 2007. [doi]
The amount of effort needed to maintain a software system is related to the technical quality of the source code of that system. The ISO 9126 model for software product quality recognizes maintainability as one of the 6 main characteristics of software product quality, with adaptability, changeability, stability, and testability as subcharacteristics of maintainability. Remarkably, ISO 9126 does not provide a consensual set of measures for estimating maintainability on the basis of a system’s source code. On the other hand, the maintainability index has been proposed to calculate a single number that expresses the maintainability of a system. In this paper, we discuss several problems with the MI, and we identify a number of requirements to be fulfilled by a maintainability model to be usable in practice. We sketch a new maintainability model that alleviates most of these problems, and we discuss our experiences with using such as system for IT management consultancy activities.