 Concerns regarding readability and the overuse of technical language were raised in studies published by the American Society of Clinical Oncology (2011), "Psychological Medicine" (2012), and "European Journal of Gastroenterology and Hepatology" (2014).Wikipedia allows anonymous editing; contributors are not required to provide any identification or even an email address.A 2007 study at Dartmouth College of the English Wikipedia noted that, contrary to usual social expectations, anonymous editors were some of Wikipedia's most productive contributors of valid content.