"I usually assume the first author is the person who actually did the research," says McNutt, a professor of earth and planetary sciences at the Massachusetts Institute of Technology. "I assum if there is a senior person who is last author, whether that's second or thid, that that is the person who probably wrote the proposal to fund the research and had the idea to begin with, but generally did not personally carry out the research.
"And then, if there is an intermdeiate author, I usually assume that is a person who had some sort of significant input--such as providing a key data set or perhaps working on some key subset of the problem--but was not the person who physically wrote the paper and did more than 50 percent of the research."
McNutt's assumptions are typical. She reads the unspoken messages of the order of authorship the way most scientists ...