Table 4. Reasons given by PIs for not naming co-reviewers to the journal editor.

Responses to the question: “Consider cases where you contributed to a peer review report and you know your name was NOT provided to the editorial staff. When discussing this with your PI, what reason did they give to exclude you as a co-reviewer?” In addition to the possible answers provided by the survey, respondents were also provided with a textbox to add write-in responses.

Reasons given by PIs for not naming co-reviewers	Number of Respondents
Did not discuss with my PI	210
Co-authorship is for papers, not for peer review reports; Intellectual contribution not deemed sufficient	33
Journal requires prior approval to share manuscript, which was not obtained; Journal does not allow ECRs to review	30
Write-in answers citing mechanistic barriers (e.g. lack of a text box to enter co-reviewer names)	3