Unpublished results hide the decline effect

"Many scientifically discovered effects published in the literature seem to diminish with time. Dubbed the decline effect...[i]t has...been reported in a string of fields — both in individual labs (including my own) and in meta-analyses of findings in biology and medicine....Some scientists attribute the decline effect to statistical self-correction of initially exaggerated outcomes, also known as regression to the mean. But we cannot be sure of this interpretation, or even test it, because we do not generally have access to 'negative results': experimental outcomes that were not noteworthy or consistent enough to pass peer review and be published. How could the availability of unpublished results be improved? I suggest an open-access repository for all research findings, which would let scientists log their hypotheses and methodologies before an experiment, and their results afterwards, regardless of outcome. Such a database would reveal how published studies fit into the larger set of conducted studies, and would help to answer many questions about the decline effect...."