“Second, groups with diverse viewpoints are the best protection against confirmatory thought. Peer review, the gold standard that epitomizes the open-mindedness and hypothesis testing of the scientific method, “offers much less protection against error when the community of peers is politically homogeneous.” In other words, the opinions of group members aren’t much help if it is a group of clones. Experimental studies cited in the BBS paper found that confirmation bias led reviewers “to work extra hard to find flaws with papers whose conclusions they dislike, and to be more permissive about methodological issues when they endorse the conclusions.”