A magazine list with brain power

Rank: A small publication uses detailed analysis to determine the 50 most influential scientists of the past 20 years.

October 27, 2003|By Michael Stroh | Michael Stroh,SUN STAFF

People magazine picks the world's sexiest men. Forbes ranks the richest Americans. U.S. News and World Report calculates the country's top colleges.

To the rankings of Hollywood beefcakes and business tycoons, add this nerdy new list: the 50 most influential scientists of the last two decades.

No. 1 on the list is the Johns Hopkins University's Bert Vogelstein. "It's nice," says the 54-year-old cancer researcher, one of four Maryland scientists to make the cut and three to land in the top 10. "Whether you're in science or not, you like to think what you're doing is making an impact."

The rankings appear in the latest issue of Science Watch, a Philadelphia-based newsletter little known outside the realm of research. Compiling them was mostly an exercise in fun, says editor Christopher King. But drawing up any best-of list naturally poses a quandary: How, exactly, do you determine the best?

As one might expect of an attempt to sort the world's most precision-obsessed profession, King steered clear of People-esque criteria such as sharpest lab coat or cutest lab rats. Instead, the newsletter turned to an increasingly influential - and occasionally controversial - practice known as citation analysis.

To understand why, let's take a brief detour into the quirky world of scientific publishing.

Printed in teeny, eye-straining type, citations are reference sources tacked to the end of almost every modern scientific paper. Flip through a research journal and citations drone by, much like the credits at the end of a blockbuster film: fascinating only to those in the business.

But this fine print plays a crucial role in the science. It acknowledges an intellectual debt and allows researchers to make a distinction between new ideas and old. Most scientists devour citations when they see a paper in their field.

"Sometimes you say, `Damn it, he didn't even refer to me," observes Johns Hopkins neuroscientist Solomon Snyder. "Or `That's nice, he gave me three references.'" Snyder, by the way, was No. 3 on the Science Watch list.

The first citations appeared in the 17th century, says Anthony Grafton, a Princeton University historian and author of The Footnote: A Curious History. They coincided with the rise of early scientific periodicals such as the Philosophical Transactions of the Royal Society of London, which made its debut in March 1665 and remains the world's oldest continuously published journal. (It was not the first however. Journal des Scavans appeared in France two months earlier.)

Citations, says Grafton, were most likely a response to scholarly spats that arose over credit for big discoveries. For example, not long before Transactions began to circulate, Italian astronomer Galileo Galilei waged a furious battle with three rival stargazers over who first observed sun spots.

"There was already a sense by the 17th century that science was not just about getting the right answer, but about being the first one to get it," Grafton says.

It wasn't until the 20th century that someone realized citations were useful for more than apportioning credit and satisfying egos. In 1955, Eugene Garfield, a young New Yorker with degrees in chemistry and library science, published an article in Science proposing a way to measure the effect of scientists on their disciplines: counting the number of times scientists cite one another's work.

The technique, which came to Garfield a few years earlier while he was toiling at Johns Hopkins' Welch Medical Library, became known as citation analysis.

A few years later Garfield started a company called the Institute for Scientific Information, hiring workers who painstakingly tapped citation after citation onto computer punch cards. Now known as ISI and owned by the Thomson Corp. of Toronto, the company pours 22.4 million new citations from 6,100 scientific journals into its database each year.

Science Watch, ISI's newsletter, uses citation databases to create lists of the hottest papers, researchers, journals and institutions - based on how often they're cited. "It's a mark of influence," says editor King. "It shows what scientists themselves view to be the most influential or significant work."

Today the technique is widely used to measure the quality of a scientist's efforts. Journals routinely promote their ISI ranking. At some universities, citation statistics directly influence departmental funding. "I've even started to see people use it on their CV," says Vogelstein, referring to curriculum vitae, a scientist's resume.

Historians of science use citation analysis to answer a variety of questions that range from where an idea originated to a list of whom a particular scientist likes and dislikes (scientists have been known to cite their friends when they can).

"Citations give you clues," says Nathaniel Comfort, a Johns Hopkins historian. "They open up new avenues for research."

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