The Lancet, one of the world’s top medical journals, has issued a new editorial policy after it published a major hydroxychloroquine treatment study that it was later forced to retract. The study, which concluded that COVID-19 patients who received the controversial drug experienced a higher fatality rate, depended on hospital data supposedly collected by a U.S. data company named Surgisphere. Only one study co-author claimed to have seen the data. Media reports later cast doubt on the data’s validity and the company’s overall existence. Under new editorial policy, more than one author on a paper must be able to view and verify the data in a manuscript. In addition, The Lancet has updated its peer review policy, now requiring editors to ensure at least one peer reviewer is capable of independently determining the validity and methodology of the dataset. For studies with extremely large datasets, a data science expert will also be required during peer review.