Using the “lead”, “equal”, “supporting” feature of CRediT

The Contributor Roles Taxonomy (CRediT), now used by thousands of academic journals, allows contributors to a project to indicate whether they contributed to each of 14 roles. CRediT also includes an optional "degree of contribution" feature which allows contributors to mark their involvement in each role as 'lead', 'equal', or 'supporting'. Although major publishers and submission systems increasingly support this feature, guidance on how the tags should be interpreted is almost entirely absent. The only semi-official guidance, which we call the JATS4R recommendation, sits in a technical tag library that most users never see or find. Moreover, that recommendation is very brief and gives no justification. We assess the JATS4R recommendation and develop several alternative guidance policies. For evaluation, we develop five pragmatic criteria: informativeness, reliability, interpretability, ease of implementation, and coherence. We find that the JATS4R recommendation performs only partially on most of them, and that its permission of multiple 'lead' contributors within a role creates a risk of degree inflation. Of the alternative guidance policies, we recommend the RESQUE policy, which permits only one lead per role and reads 'equal' as 'equal lead'. We also present JATS4R-revised, a clarified version of the JATS4R recommendation that does as well as RESQUE on our criteria but permits multiple leads, which suits large collaborations spanning disciplines and sites, at the cost of a greater risk of degree inflation. We discuss how to weigh these trade-offs, recommend that journals state which policy they use, and close with guidance on reporting degrees of contribution in CVs.