Analysts focus on publication and citation data to reveal the size and structure of materials science research globally.
In the last few decades, scientific research publications have made a transition from the printed page to digital versions of journals on the Web. At the same time, the indexing of journal contents has made the same passage from printed indexes to electronic databases.
Thomson Reuters, New York, which indexes scientific journal literature, has made this data available in its Web of Knowledge platform. Its primary use is to allow researchers to find the articles they need to conduct their work. Another Thomson Reuters group, which tabulates publications in the indexed journals and how often they are cited, uses the database to assess research activity and performance by field, over time, and on the part of nations, institutions, and individuals.
This second activity, which government agencies increasingly draw on to set national science strategy and allocate funding, is known as bibliometrics or scientometrics. The numbers derived from bibliometric analysis describe the who, what, when, and where of research and serve as a contemporary commentary on scientific activity.
In June, Thomson Reuters published Global Research Report: Materials Science and Technology, authored by analysts Jonathan Adams and David Pendlebury. They report that China published some 55,000 journal articles in materials science over the last five years, whereas the United States produced about 38,000.
Analysts have long known that such simple numbers can’t reveal the true importance of the papers published in each country. Without more information to indicate the strength of this research, paper-by-paper, they cannot know its true impact. Adams and Pendlebury, therefore, analyzed not only production but influence as measured by the number of times a nation’s papers were cited.
The researchers assembled their data from a specific database within the Web of Knowledge called the Web of Science, which covers the contents of about 12,000 of the highest impact journals worldwide. It’s the online version of what used to be known in print as the Science Citation Index. The database is bibliographic, not full text, but its strength, says Pendlebury, is in its citations.
“A citation index offers the opportunity to do two things. You don’t have to rely on key terms or traditional subject indexing to find relevant articles. You can navigate the network of associations that the researchers themselves reveal when they add references to their papers,” says Pendlebury. “The second benefit is that these citations represent a form of repayment of intellectual debts, credits in other words. One researcher formally recognizes that he or she drew upon the work of another.”
Citation measurements like these correlate strongly with what experts believe is the best work, he says.
In terms of national and institutional performance, the researchers looked at the last 30 and 10 years, respectively. In terms of specialty areas, or so-called research fronts, they looked at the last five years. Adams and Pendlebury also consulted R&D Magazine’s 2011 Global R&D Funding Forecast and found that materials research has enjoyed, globally, a 10% rise in the last three years.
Pendlebury says that the report clearly reveals the dominance of Asian nations and a comparative decline of the United States and the European Union. The United States, in particular, held the lead in materials science in the 1980s but its output has fallen by nearly half—from 28 to 15%.
A declining world share is not unusual, says Pendlebury, because developing nations are producing papers faster than developed nations, but the amount of the decline was a surprise, particularly when compared to U.S. performance in other scientific research fields in the late 1990s. Output has recovered to about what it was in the late 1990s, however.
Scientific impact differs greatly from raw output and by using the citations index information, the study found that more established nations held the lead in citations per paper, as shown in table 1.
|Table 1. Publication counts, citation counts, and citations per paper (impact) scores materials science research indexed in Web of Science for leading countries in the Asia-Pacific region and two key comparators, ranked by impact (2005-2009). Source: Thomson Reuters|
The United States and the European Union are still dominant in per-paper influence, and the United States is particularly strong, earning an average of 73% more citations per paper than the world average. However, both hold shrinking shares. According to Adams, Asia’s low citations-per-paper average in this field, relative to the United States and European nations, masks a wide range of scores among some Asia-Pacific nations and individual institutions that in fact produce papers with high citation impact. Singapore as a nation and the National University of Singapore as an institution are examples of high performance in the field, he says.
“Asia has placed a lot of chips on this field. They’ve made the connections between basic and applied research,” says Pendlebury. Asia’s investments in a robust research infrastructure will eventually produce high-level research, he says, so impact scores from countries like China will continue to increase.
The report can be viewed here: