Figure 2. Experiences of co-reviewing and being invited to review.

(A,B) Responses to question: “How many times in your career have you contributed ideas and/or text to peer review reports where you are not the invited reviewer (e.g. the invited reviewer is the PI for whom you work)?” 73% of all respondents (366/498) had participated in co-reviewing: 63% of this subsample had carried out co-reviewing activities on 1–5 occasions; 33% on 6–20 occasions; and 4% on more than 20 occasions. (B) Number of co-reviewing experiences by career stage for 401 ECRs: the distribution of postdocs (n = 312) is skewed toward more co-reviewing experiences, whereas the distribution of PhD students (n = 89) is skewed toward fewer co-reviewing experiences. (C) Responses to question for ECRs: “How many times in your career have you reviewed an article for publication independently, i.e. carried out the full review and been identified to the editorial staff as the sole reviewer?” 55% of the ECR respondents (218/401) had never carried out independent peer review, and 46% (183/401) had carried out independent review as the invited reviewer: 115 had done so 1–5 times, 57 had done so 6–20 times, and 11 had done so more than 20 times.