Evaluation of clinical information systems. What can be evaluated and what cannot?

The evaluation of clinical information systems is essential as they are increasingly used in clinical routine and may even influence patient outcome on the basis of reminder functions and decision support. Therefore we try to answer three questions in this paper: what to evaluate; how to evaluate; how to interpret the results. Those key questions lead to the discussion of goals, methods and results of evaluation studies in a common context. We will compare the objectivist and the subjectivist evaluation approach and illustrate the evaluation process itself in some detail, discussing different phases of software development and potential evaluation techniques in each phase. We use four different practical examples of evaluation studies that were conducted in various settings to demonstrate how defined evaluation goals may be achieved with a limited amount of resources. This also illustrates advantages, limitations and costs of the different evaluation methods and techniques that may be used when evaluating clinical information systems.