Which peer reviewers voluntarily reveal their identity to authors? Insights into the consequences of open-identities peer review

Identifying reviewers is argued to improve quality and fairness of peer
review, but is generally disfavored by reviewers. To gain some insight
into the factors that influence when reviewers are willing to have their
identity revealed, I examine which reviewers voluntarily reveal their
identities to authors at the journal Functional Ecology, at which reviewer
identities are confidential unless reviewers sign their comments to
authors. 5.6% of reviewers signed their comments to authors. This
proportion increased slightly over time, from 4.4% in 2003-2005 to 6.7% in
2013-2015. Male reviewers were 1.8 times more likely to sign their
comments to authors than were female reviewers, and this difference
persisted over time. Few reviewers signed all of their reviews; reviewers
were more likely to sign their reviews when their rating of the manuscript
was more positive, and papers that had at least one signed review were
more likely to be invited for revision. Signed reviews were, on average,
longer and recommended more references to authors. My analyses cannot
distinguish cause-and-effect for the patterns observed, but my results
suggest that “open identities” review, in which reviewers are not
permitted to be anonymous, will likely reduce the degree to which
reviewers are critical in their assessment of manuscripts and will
differentially affect recruitment of male and female reviewers, negatively
affecting the diversity of reviewers recruited by journals.