Peer review is a term of art covering a set of practices that collect and apply the judgement of expert reviewers (identified as "expert," not just "knowledgeable"—so the designation is a political justification as well as a substantive one) to decisions about which manuscripts to publish, which proposals to fund, and which programs to sustain or trim. Peer review and its variants are preferred in science not only because they bring appropriate expertise to bear on decisions, but also because they assert the professional autonomy of scientists. The review of original ideas grounded in acceptable evidence certifies the accuracy, validity, and heuristic value of results. Peer reviewers are collegial critics who contribute uniquely to this competitive negotiation process by allocating scarce resources—money, time, space—and the career capital they help to generate. Outcomes based on peer review thus concentrate or disperse available resources over...