Assessment of Software Maintainability of openEHR Based Health Information Systems – A Case Study In Endoscopy

Maintaining health information systems over time requires significant effort and time. This is especially marked in clinical information systems where most, if not all, functional software requirements are dependent on healthcare concepts and processes which are prone to high rate of change. Software engineering literature indicates that maintenance tasks alone may constitute 70-80% of the total development cost. It has been suggested that openEHR based systems will effectively tackle this by separating domain knowledge from software code. The objective of this paper is to assess the maintainability of an openEHR based clinical application with comparison to another application based on the same functional requirements but implemented using traditional development methods. An endoscopy reporting application (GastrOS) driven by openEHR archetypes has been implemented using .Net/C#. It has the same functionality and appearance as an existing application which has been developed using Object/Procedural approach with relational data modelling. Afterwards a number of change requests have been implemented in both systems while assessing maintainability using metrics defined in the ISO/IEC 9216 and 25000 software quality standards. This paper presents the implementation methodology and preliminary results of the larger evaluation study using a more comprehensive set of change requests. These results indicate that, on average, the openEHR based application took approximately nine times less time to implement the change requests and were seven times less complex compared to the other application. While essentially a quantitative study it equally presents qualitative findings about opportunities and limitations of taking a model driven approach in development.