Enlarge / She may work hard, but she's likely to get less credit for it. (credit: Qi Yang )

In science, the ultimate measure of academic worth is the number of papers published where you're credited as an author. There are subtleties that matter—where you are in the list of authors and whether others cite your publications. But it's hard for those factors to overcome the weight of raw numbers. Other things, like grants and promotions, also matter a great deal. But success in those areas often depends on a large publication list.

That's why a publication released on Wednesday by Nature is significant: It describes data that indicate that women are systematically left off the list of authors of scientific publications. The gap between participation and publication continues even after various factors of career advancement are considered. And it goes a long way toward explaining why science has a problem called a "leaky pipeline," where women drop out of research at higher rates at each stage of their careers.

Making the team

It's pretty easy to crunch the data and see that women are underrepresented in author lists attached to scientific papers. But figuring out why is a significant challenge. It could result from women being historically underrepresented in some fields, discrimination, or differences in effort and commitment. Figuring out which factor(s) contribute is challenging because it involves identifying an invisible population: the people who should be on the author list but aren't.