Authorship and contribution disclosures

Abstract

Most scientific research is performed by teams, and for a long time, observers have inferred individual team members' contributions by interpreting author order on published articles. In response to increasing concerns about this approach, journals are adopting policies that require the disclosure of individual authors' contributions. However, it is not clear whether and how these disclosures improve upon the conventional approach. Moreover, there is little evidence on how contribution statements are written and how they are used by readers. We begin to address these questions in two studies. Guided by a conceptual model, Study 1 examines the relationship between author order and contribution statements on more than 12,000 articles to understand what information is provided by each. This analysis quantifies the risk of error when inferring contributions from author order and shows how this risk increases with team size and for certain types of authors. At the same time, the analysis suggests that some components of the value of contributions are reflected in author order but not in currently used contribution statements. Complementing the bibliometric analysis, Study 2 analyzes survey data from more than 6000 corresponding authors to examine how contribution statements are written and used. This analysis highlights important differences between fields and between senior versus junior scientists, as well as strongly diverging views about the benefits and limitations of contribution statements. On the basis of both studies, we highlight important avenues for future research and consider implications for a broad range of stakeholders.

Fig. 1. Share of authors performing a particular contribution; stacked for each author position.

Teams with six authors. For example, 78% of first authors conceived (blue segment), 87% performed (brown), 27% provided materials (green), 94% analyzed (orange), 86% wrote (turquoise), and 5% contributed “other” (red). Summing these percentages (377%) shows that the average first author made 3.77 different contributions.

Fig. 2. Variation in author contributions by team size.

(A) SD of the count of contributions, by position and team size. (B) Share of articles deviating from conventions regarding count of contributions, by position and team size.

Fig. 3. Share of authors in each position that meet criteria (i) and (ii) of the ICMJE requirements for authorship (in their less strict interpretation, see Materials and Methods for details).

Fig. 4. Informational advantages of author order and contribution statements.

Ratings with respect to types of contributions (A), share of effort (B), importance of contributions (C), and share of credit (D).

Fig. 5. Process by which contribution statements are made.

Authors who discussed statements (A) and authors who explicitly approved statements (B).

Fig. 6. Perceived incidence of ghost and guest contributorship.

Incidence of ghost contributorship (authors not listed with contributions they have made) by senior authors (A) and junior authors (B). Incidence of guest contributorship (authors listed with contributions not made) by senior authors (C) and junior authors (D). By seniority of respondent.