[Decisions of the Federal Joint Committee for rejecting work with "weak" or failing evidence].

With the aim to study the level of evidence on which coverage decisions of the Federal Joint Committee (G-BA) were made and how the G-BA deals with missing or insufficient evidence, we analysed the final reports of coverage decisions after benefit assessments (outpatient care) between 1.1.1998 and 31.10.2008. A total of 36 decisions were analysed. 12 technologies were adopted for provision in outpatient care, 22 were excluded and two were suspended of assessment procedure until new evidence is provided. The G-BA decided in each case on the basis of the best available evidence. In the majority of negative decisions (16 of 22) no randomised controlled trials (RCTs) were available, the decision was therefore made on the basis of non-randomised studies. Even five of 12 positive decisions lacked evidence based on RCTs. In these cases the G-BA acknowledged that the evaluation of efficacy in randomised clinical trials was, due to the disease characteristic, not feasible. The G-BA uses different ways to deal with missing or insufficient evidence. It should be noted that the concept of missing evidence in the public is often diffuse and should be better defined.