A qualitative study of Equal Co-First Authorship.

Over the past several years, there has been a significant increase in the number of scientific articles with two or more authors claiming "Equal Co-First Authorship" (ECFA). This study provides a critical background to ECFA designations, discusses likely causes of its increased use, and explores arguments for and against the practice. Subsequently, it presents the results of a qualitative study that sought the opinion of 19 authors listed among equal first authors of recent publications in leading scientific journals about ECFA designations. Results show that circumstances leading to ECFA designations vary significantly from each other. While the development of policies for these situations would not be easy, participants suggested that the lack of clear and consistent policies regarding the attribution and evaluation of ECFA contributes to tensions amongst ECFA authors and obscures their preferred attributions of credit.