title: [Evidence level Ia--is the gold standard of scientific evidence as attractive as its reputation?].
abstract: Here we raise the question as to whether the highest standard of valid statements, the meta-analysis, really earns its reputation and needs no further testing. For that purpose we formulated the hypothesis that the evaluation of clinical studies and meta-analyses is largely based on subjective criteria, which have hitherto not been sufficiently standardised. To support this hypothesis, we present scientific evidence on three topics: 1) Studies included in meta-analyses do not always meet the quality demands for inclusion in a meta-analysis. 2) The comprehensive results of a meta-analysis, which is read by scientists, do not always correspond with the summary in the same meta-analysis, which is read by politicians and decision makers in the health-care system. 3) Every scientist who does not want to relinquish his/her autonomy will decide for him- / herself whether new scientific data (external evidence) is sufficiently valid and convincing to change his/her previous conviction (internal evidence) should this not coincide with the new data. This process is always subjective and individual. We believe we can prove with sufficiently valid methods that even meta-analyses require testing, which can only be guaranteed by the scientific community itself. This guarantee must be reliable, i. e., pseudoevidence must be avoided because society will otherwise lose trust in the achievements of the scientific community and orient itself towards other statements, which may be subject to less methodically stringent proof.
authors.affiliation: Klinische Okonomik, Universität Ulm. franz.porzsolt@uniklinik-ulm.de
authors.forename: F
authors.initials: F
authors.lastname: Porzsolt
mesh_terms: D019985:Benchmarking / Q000592:standards* / Q000706:statistics & numerical data; D015982:Bias; D019317:Evidence-Based Medicine / Q000592:standards* / Q000706:statistics & numerical data; D005858:Germany; D006705:Homeopathy / Q000592:standards / Q000706:statistics & numerical data; D006801:Humans; D015201:Meta-Analysis as Topic; D016032:Randomized Controlled Trials as Topic / Q000592:standards / Q000706:statistics & numerical data; D015203:Reproducibility of Results; D016896:Treatment Outcome