[The] problem of irreproducibility is tied to a bias in science toward positive results. This bias towards the positive operates on many levels in science, including a “publication bias” of only publishing positive results and discarding, if not dismissing, negative results. The bias toward positive results including setting up experiments to capture positive results, which means that of course more positive results will be found. Or to keep experimenting until one does get positive results.
Kevin Kelly — Irreproducible Results