Co-First/Equal authorship is when two or more individuals are noted as providing the same or equal contribution(s) to a published work. To find this information in a full text or PDF article, first locate the article in PubMed (or another database), link to the publisher’s site (using the buttons in the upper right corner of a record), download the full text where possible, and check both the “Author Affiliation” and “Footnotes” sections (if one exists) to see if there is any mention of co-first/equal authorship for the research—this is where this information is usually listed.

Here’s an example of co-first authorship on a paper: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0000396. Notice the CO icon next to each of the first authors—hover over this icon to see a complete description. Continue reading →