Sunday, November 6, 2016

Scientists can publish their best work at any age

Hoping that your next paper will be the big one? It just might be — the chance that your next article will be your best-cited is as good as ever, no matter where you are in your career.

That’s the finding of a team led by Albert-László Barabási at Northeastern University in Boston, Massachusetts. The researchers analysed the papers of thousands of scientists from different disciplines. Considering their publication records as a sequence of articles, the most highly-cited were equally likely to be found at the beginning, middle or end of the sequence.

“We scientists are random,” Barabási says. “Every time we publish a paper, we have the same chance of publishing our biggest hit as we do with any other paper.”

This might seem to conflict with the well-documented finding that big discoveries and high-impact work tend to happen early in a scientist’s career. But there’s no contradiction, because the new work also shows that productivity — the number of papers produced per year — tends to slowly decline over a typical career. A scientist’s chance of securing a ‘greatest hit’ accordingly decreases over time, simply because they have fewer shots at it.

But the researchers also make a more contentious calculation. They devise a simple mathematical model that describes the probability that any particular paper will be a hit. This depends on only two factors, they argue: an element of luck, and a certain quality, or Q factor, that measures an individual scientist’s ability to boost the impact of any project.

Testing their model against the publication records of 2,887 physicists, the team found that the equation implies that the ‘luck’ factor is the same for all scientists. The Q factor is obtained from a researcher’s citation record: it is proportional to the logarithm of the number of citations that a scientist has received over a certain time frame.

The researchers anticipated that Q would increase over the course of a scientific career, as an individual becomes more experienced. To their surprise, they found that it remains mostly constant.