"... a fundamental aspect of scientific inquiry: the importance of context. In a paper published on Monday in the Proceedings of the National Academy of Sciences, my collaborators and I shed new light on this issue. Our results suggest that many of the studies failed to replicate because it was difficult to recreate, in another time and place, the exact same conditions as those of the original study."

http://www.nytimes.com/2016/05/29/opinion/sunday/why-do-so-many-studies-fail-to-replicate.html