With their ever-growing importance and usability, the healthcare sector has been investing heavily in medical information systems (IS) in recent years, as part of the effort to improve medical decision-making and increase its efficiency. This research aims to evaluate the contribution of information technology (IT) to improving the medical decision-making processes and to evaluate the degree to which IT investments are worthwhile. The method included the assessment of normative value of information. A decision tree model was developed. The calculated tree results were summarized in a cost-effectiveness analysis and a return on investment (ROI) analysis. This research aim to contribute: Researchers - by providing insights regarding decision theory, value of information and medical informatics; Practitioners - by promoting the design of medical IS; Physicians - by enhancing efficient use of information resources; Patients - by improving healthcare services; Policy decision-makers - regarding the advisability of investing and managing medical IS.