Replication crisis

The replication crisis (or replicability crisis) refers to a methodological crisis in science in which scientists have found that the results of many scientific experiments are difficult or impossible to replicate on subsequent investigation, either by independent researchers or by the original researchers themselves. While the crisis has long-standing roots, the phrase was coined in the early 2010s as part of a growing awareness of the problem.

Since the reproducibility of experiments is an essential part of the scientific method, the inability to replicate the studies of others has potentially grave consequences for many fields of science in which significant theories are grounded on unreproduceable experimental work.

The replication crisis has been particularly widely discussed in the field of psychology (and in particular, social psychology) and in medicine, where a number of efforts have been made to re-investigate classic results, and to attempt to determine both the validity of the results, and, if invalid, the reasons for the failure of replication.

According to a 2016 poll of 1,500 scientists reported in the journal Nature, 70% of them failed to reproduce another scientist's experiments (50% failed to reproduce their own experiment). These numbers differ among disciplines:

In 2009, 2% of scientists admitted to falsifying studies at least once and 14% admitted to personally know someone who did. Misconducts were reported more frequently by medical researchers than others.

Out of 49 medical studies from 1990–2003, with more than 1000 citations, 45 claimed that studied therapy was effective. Out of these studies, 16% were contradicted by subsequent studies, 16% inflated effectiveness of therapy and 24% were not replicated.Food and Drug Administration in 1977–90 found flaws in 10–20% of medical studies. In a paper published in 2012, Glenn Begley, a biotech consultant working at Amgen, and Lee Ellis, at the University of Texas, argued that only 11% of the pre-clinical cancer studies could be replicated.

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