Bestaat 'passend' bewijs?

The 'levels of evidence' system, which dates back to the 1980s, ranks studies based on the strength of the corresponding study design. Level sets have been developed for studies of interventions, for test accuracy research, and many other forms of clinical research. For some authors, practicing evidence-based medicine has become identical to assigning levels of evidence. This is unfortunate, because more modern systems to come out of the evidence-based medicine movement, such as GRADE, distinguish between the credibility of evidence (which is not just affected by the selected design), the magnitude of the effect, and the applicability of the findings to the clinical question at hand. A new system - :fitting evidence" - has recently been developed by the Dutch Health Care Insurance Board, to evaluate evidence for reimbursement decisions. That system, with an 18-item checklist, looks at threats to the internal validity of studies as well as to the feasibility of randomized comparisons, to see whether it is "fitting" to design a randomized trial. It is unclear yet how these evaluations can and should be combined in the appraisal of the strength of the existing evidence