Important healthcare decisions that concern a patient’s health should always proceed from the best available scientific evidence in order to improve quality of care through the identification and promotion of practices that work, and the elimination of those that are ineffective or harmful. Evidence-based medicine (EBM) was originally defined as "the integration of current best evidence with clinical expertise and patient values" (1). EBM is not a cookbook but a useful tool for decision making. There are four steps in incorporating the best available research evidence in decision making: asking answerable questions; accessing the best information; appraising the information for validity and relevance; and applying the information to patient care. This, as well as identification of important knowledge gaps, can be done through systematic literature reviews. Diagnostic methods differ from therapeutic methods and it is sometimes difficult to establish a connection between results from a diagnostic test with patient outcomes. The benefits associated with the use of a specific diagnostic method depend on performance characteristics such as sensitivity and specificity as well as prevalence of the disease. The fact that diagnostic methods affect short-term outcomes rather than longterm patient outcomes make evaluation of diagnostic tests more complicated than the evaluation of therapeutic methods. The efficacy of diagnostic imaging methods can be evaluated according to a hierarchical approach as described by Fryback and Thornbury (2). This approach includes six levels of efficacy where efficacy at higher levels is contingent on efficacy at all lower levels. As a tool to assess the quality of studies on diagnostic imaging the QUADAS protocol has been suggested (3). Examples of systematic literature reviews in oral- and maxillofacial imaging, assessed according to the QUADAS protocol, will be given. Few studies deal with the upper levels of the Fryback and Thornbury model and the costs and effects of imaging methods at the patient outcomes and societal levels have rarely been considered. (1) Sackett DL et al. Evidence based medicine: what it is and what it isn't. 1996. Clin Orthop Relat Res 2007;455:3-5. (2) Fryback DG, Thornbury JR. The efficacy of diagnostic imaging. Med Decis Making 1991;11:88-94. (3) Whiting P et al. The development of QUADAS: a tool for the quality assessment of studies of diagnostic accuracy included in systematic reviews. BMC Med Res Methodol 2003;3:25.