An online poll answered by more than 4,300 Nature readers suggests that most researchers have felt pressured by peer reviewers to cite studies in their papers that seem unnecessary.

Readers were asked, ‘Have you ever felt pressured by peer reviewers to cite seemingly superfluous studies in your work?’, to which 66% responded ‘yes’ and 34% said ‘no’ (see ‘Coercive citation?’).

The poll accompanied a news story last month, which revealed that the Dutch publisher Elsevier had found a small proportion of academics reviewing papers for its journals were exploiting the review process by asking authors to reference the reviewers’ own papers in exchange for a positive report.

This practice is broadly labelled ‘coercive citation’, and can involve journal editors or peer reviewers pressuring authors to cite particular studies to boost their own citation count or their journal’s impact factor.

Eric Fong, who researches management at the University of Alabama in Huntsville and has studied coercive citation, says reviewers have a lot of power in the publication process. “I recognize that pressure can be subtle and that comments can be written in ways that make them seem legitimate, which then may make it past the editor,” Fong says. He adds that if authors feel that adding these citations is necessary to get a positive review, journal editors need to take some responsibility for the problem.

The proportion of researchers who reported experiencing this kind of pressure in the latest poll is higher than in other surveys. In a 2012 survey of more than 6,600 researchers in social sciences and business fields, one in five reported being asked by journal editors to include superfluous citations, potentially to boost their title’s visibility and impact factor. And in a 2017 survey of more than 12,000 academics, about 14% of respondents reported instances of coercive citation.

The difference could be down to the Nature poll’s limitations: respondents were self-selecting and people who have been affected or are interested in coercive citation may be more likely to respond. Whether citations are ‘superfluous’ is likely to be subjective in some cases, and respondents were not asked whether reviewers were asking for their own studies to be cited.