Evidence-based health informatics (EBHI) is a key concept in the development and deployment of IT systems and applications in an ethical, efficient and effective health system. There is an ever growing body of knowledge to guide IT-related decision making, but further growth of this body of knowledge is required as the health IT domain and technologies are continuously evolving, leading to new functionalities and applications. However, EBHI should not wait until retrospective evidence is available – increasingly policy makers should draw on available prior and external evidence to influence design and development processes so as to ensure that health IT is devised in response to a delivery process need and not as an IT driven goal. EBHI should thereby seek to move forward significantly the metric that only some 20% of IT investment is truly successful.