Nanotechnology publications and citations by leading countries and blocs

Kostoff et al. (2007) also present national nanotechnology publications comparisons. We differ here in considering leading countries and blocs of special interest, and addressing total citations as well as publications. Kostoff et al. (2007) do limited national ranking based only on share of 1998 papers with >120 cites and 2002 papers with >79 cites—with the particularly interesting finding that China’s share of most cited papers increases from 1.4 to 5.8% in that span.

In this article, the European Union is taken to comprise the 27 member countries (EU27) at the time we undertook the analysis. These countries are: Belgium, Bulgaria, the Czech Republic, Denmark, Germany, Estonia, Ireland, Greece, Spain, France, Italy, Cyprus, Latvia, Lithuania, Luxembourg, Hungary, Malta, the Netherlands, Austria, Poland, Portugal, Romania, Slovenia, Slovakia, Finland, Sweden, and the United Kingdom.

Although the focus in the present article is on large countries and blocs, we note that a few individual highly-developed small countries (mostly in Europe, including Switzerland and the Netherlands) have comparable or higher normalized quality impact factors in nanotechnology than the US, although their scale of output is far less.

Our approach builds upon prior experience in developing a large-scale bibliometric database of nanotechnology publications (as discussed in Heinze et al. 2007). In further refining our method, we reviewed a number of alternative nanotechnology search strategies, including strategies developed at UCLA’s Nanobank (Zucker and Darby 2005) and in Europe (Zitt and Bassecoulard 2006), and consulted with several experts in nanotechnology and bibliometrics. We decided on a two-stage Boolean search rather than the bootstrap or lexical clustering approaches used by these colleagues, judging that this two-stage method provided the capability to fine-tune the search algorithm to ensure precision and timeliness. As we implemented our search strategy, we benefited from an in-depth (“item by item”) review by Prof. Angus Kingon (North Carolina State University). We also benefited from significant interaction with Dr. Ron Kostoff (Office of Naval Research), see especially Fig. 4 in Porter et al. 2007 that indicates quite comparable coverage with Kostoff et al. 2007. The resulting search algorithm was further tuned and validated through review by 19 researchers with nanotechnology expertise (Porter et al. 2007).

We experimented with the calculation of an h-index by country. The h-index is a measure that seeks to combine publication productivity and scientific impact (an index of h results from a researcher publishing h papers each with at least h citations, see Hirsch 2005). The results for citations in 2003 gave us h-index numbers as follows: US: 92; EU27: 70; Germany: 46; Japan: 44; and China: 43. This result suggests that the US retains an edge in quality of nanotechnology research despite dramatic gains of other countries in terms of quantity of research. However, the weight to be given to differences in these index figures is hard to estimate and it has not been recommended to apply the h-index to groups of researchers (Hirsch 2005).

Nanotechnology publication in Chinese-language journals has continued to grow in recent years, although at a significantly lower rate than for nanotechnology publication by Chinese authors in English-language journals (Lin and Zhang 2007). There are substantial incentives for Chinese researchers to publish in English-language ISI journals; field research in China in 2007 by one of the authors of this article confirms that many leading Chinese nanotechnology researchers now publish mostly in English. Additionally, as Lin and Zhang note, Chinese-language nanotechnology publication is often a bridge to communicate results available in English to exclusively Chinese-speaking researchers and is typically not at the research frontier. Hence, while we expect that using SCI does undercount China’s total publication effort, available evidence suggests a relatively smaller effect on underestimating China’s overall scientific quality. However, further bibliometric investigation on the quality of Chinese-language nanotechnology publication is necessary to more systematically estimate these effects.