The study was inspired by anecdotes from authors who cited articles only because reviewers asked them to, says study author Adrian Barnett, who researches peer review and metaresearch at Queensland University of Technology in Brisbane, Australia. Sometimes, these requests are fine, he says. But if reviewers ask for too many citations or the reason to cite their work is not justified, the peer-review process can become transactional, says Barnett. Citations increase a researcher's h-index, a metric reflecting the impact of their publications.