From the We-Already-Knew-That department: A new study published in EMBO Reports confirms that being a middle author on a paper lessens your stature dramatically, even if the paper is published in a prestigious journal. "Our survey results showed that author names appearing near the beginning of the list of authors are perceived to have contributed more to the project," wrote Jonathan Wren of the Oklahoma Medical Research Foundation, first author on the paper, in a press release. Senior authors--those listed last--tend to maintain their standing no matter how many authors are listed in the byline.
In case you were wondering, the authors least likely to get credit for the new study--those listed in the middle--are Katarzyna Z. Kozak of the Department of Internal Medicine, Exempla Saint Joseph Hospital, Denver, Colorado, Kathryn R. Johnson of the Department of Dermatology, Sara J. Deakyne the Department of Pediatrics, and Lisa M. Schilling of the Department of Medicine--all of University of Colorado, Aurora, Colorado. The last, senior, author is Robert P. Dellavalle of the Veterans Affairs Medical Center, University of Colorado, Denver, Colorado.
Though I obviously am in no position to question the author order on this paper, I can't resist pointing out that the first and last authors are both men and all the middle authors are women...
...which may go part way towards explaining why (from the same issue of the same journal):
Women are more likely to quit at the postdoc to principal investigator transition
Traditional Gender Roles Hold Back Female Scientists.