Policy Concentrates PUBLISHING
Sorting out scientific success Researchers’ most successful papers come at random times in their careers, a study shows versity. She and her colleagues used number of citations, a common but incomplete way to measure a paper’s impact, as a proxy. At first, they found that scientists are most productive in early and midcareer. But when they dug deeper into their data on thousands of scientists, they saw that early success is because early and midcareer scientists publish more often. In fact, whether any particular paper got a high number of citations was random throughout scientists’ careers. “Any paper published by a scientist could be the best one,” Sinatra says, pointing out that scientists have made Nobel Prize-winning discoveries in grad school and after retirement. That was true across disciplines and across various types of research. There were a small percentage of scientists who stood out for having higher citations overall. Their analysis found that success was partially luck and partially an
This visualization shows that scientists tend to publish just a handful of highly cited papers in their careers. Each peak represents the number of citations an individual paper received. unidentified factor they call Q. The researchers’ next step is figure out what factors drive Q, such as their institution or their gender, Sinatra says. The paper is a valuable contribution to understanding scientific success, Packalen says, but he doesn’t think it should guide funding just yet. “You don’t want to make science policy based on impact alone.”—ANDREA WIDENER
CHEMICAL REGULATION
DHS seeks advice on bomb chemicals Eight years ago, Congress required DHS “to prevent the misappropriation or use of ammonium nitrate in an act of terrorism” by regulating its sale and transfer. The The Department of Homeland Security monsense approach for restricting access to fertilizer was used in the 1995 bombing of (DHS) has a homegrown explosives dilemthe chemicals that can be used for both legit- a federal building in Oklahoma City that ma: how to keep explosive precursor chem- imate and illegitimate purposes, Wulf said. killed 168 and injured hundreds of others. icals, such as ammonium nitrate, out of DHS proposed an ammonium nitrate the hands of would-be bombers without rule in 2011, but it has yet to finalize redisrupting industries, such as agriculstrictions on the chemical. ture, that rely on these substances. Wulf said the legislation’s narrow At the behest of DHS, a committee focus on ammonium nitrate has made of the National Academies of Sciences, it challenging for DHS to complete Engineering & Medicine began studying the rule. Such restrictions could shift this issue in late October. The panel would-be bombers to other explosive includes chemists and engineers with chemical precursors, he explained. expertise in explosives materials. DHS is asking the National AcadeDHS has a good handle on the level mies committee to identify chemicals of threat posed in the U.S. from improthat have been used or are likely to be vised explosive devices (IEDs), accordused in IEDs and analyze how these ing to David Wulf, a Homeland Security chemicals move through the supply division director. In addition, DHS chain. DHS wants the committee to priknows which “chemicals can be made to Ammonium nitrate, a common agricultural oritize the chemicals for control. go boom.” chemical, was used in the 1995 bombing of the The committee expects to complete The department is looking for a comMurrah Federal Building in Oklahoma City. its report in 2017.—JESSICA MORRISON
National Academies is studying ways to control availability of substances used in improvised devices
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C&EN | CEN.ACS.ORG | NOVEMBER 7, 2016
CREDIT: JIM BOURG/REUTERS/NEWSCOM (BUILDING); KIM ALBRECHT/ROBERTA SINATRA (DATA VISUALIZATION)
Conventional wisdom has long claimed that scientists publish their most important work early in their careers. Now, a study suggests that might be solely because younger scientists publish more. The research found that almost any paper could become a scientist’s most successful, no matter when it was published during that person’s career (Science 2016, DOI: 10.1126/science.aaf5239). “In some ways, this is bad news for scientists who believe the next paper they write is the best—because that is probably false,” says University of Waterloo economist Mikko Packalen, who studies science but was not involved in this research. The paper’s authors wanted to look at what drives scientific success. “How does impact evolve in a career, and can we predict who will make a big discovery?” asks physicist Roberta Sinatra from Northeastern University and the Central European Uni-
