The latest list of the world's most highly cited researchers features few scientists based in developing countries - and none from Africa outside South Africa - exposing the North-South divide and raising questions on how the impact of science is measured.
Thomson Reuters has issued its The World's Most Influential Scientific Minds: 2014 report based on analysis of recent citations of published papers across science.
But only 86 out of the approximately 3,200 scientists on the list are affiliated with institutions in the developing world. And they are based in only 12 countries, with most in Saudi Arabia, Iran, India and Turkey, whose combined count is 63.
David Pendlebury, a citations specialist who produces the list and report for Thomson Reuters, says that, clearly, there is a "strong correlation between GDP and citation measures. Pursuing scientific research to a global standard requires significant investment."
Access to opportunities is also a factor, according to Louise Bloom, research officer at the Humanitarian Innovation Project, University of Oxford.
"Unfortunately there are a lot of inequalities that developing countries face," she says. "Not many people have had as many opportunities in accessing education but they still have the skills, desire and demand for more scientific development."
She says that influential scientific minds from developing countries "do exist but they're probably not recognised as much as they should be globally".
Citations: not the whole story
Pendlebury says that while analysing citation data can be helpful, it does not tell the whole story.
"Citation measures have been reliably used for four decades as partial indicators of scientific advancement but they do not tell the entire story since there is much important research that is less well captured by these data."
Pendlebury says aspiring to be on a citations list should not be the aim for scientists. "The goal for scientists should not be citation status but excellence in their own research, whatever that topic may be. Some topics will have more practical or local relevance than others," he says.
"Whatever the topic, excellent research will result in a strong citation record, but certain work that is more applied may not be represented in the citation record as much," Pendlebury adds.
Those who use such work, such as clinicians, engineers, or farmers, for example, "don't typically write scientific papers and record their use in references or footnotes".
"Practical and locally important research is not second place to fundamental and internationally recognised research," he adds.
A separate profiling system for more practical researchers would be a good idea, he admits. "But the question is, what data would serve to distinguish these individuals?"
Nevertheless, he says that the origin of scientists on the list is changing "as scientific research becomes more globalised and less dominated by Europe and North America.
"This century will see the production of scientific research more evenly distributed than before. We have witnessed the dramatic rise of Asia as a research producer; China is a case in point, but also South Korea, Taiwan, and Singapore. Malaysia and Thailand are now rapidly developing as well, but still somewhat behind the others."
Link to chart: http://cf.datawrapper.de/eRVRt/1/
Link to map: http://cdb.io/1rv3jw7