Trends of citations in scientific literature

As reported by the BBC:

China is on course to overtake the US in scientific output possibly as soon as 2013 - far earlier than expected. That is the conclusion of a major new study by the Royal Society, the UK's national science academy...

The figures are based on the papers published in recognised international journals listed by the Scopus service of the publishers Elsevier...

Professor Sir Chris Llewellyn Smith, chair of the report, said he was "not surprised" by this increase because of China's massive boost to investment in R&D. Chinese spending has grown by 20% per year since 1999, now reaching over $100bn, and as many as 1.5 million science and engineering students graduated from Chinese universities in 2006.

According to the report, "The scientific league tables are not just about prestige - they are a barometer of a country's ability to compete on the world stage"...

However the report points out that a growing volume of research publications does not necessarily mean in increase in quality. One key indicator of the value of any research is the number of times it is quoted by other scientists in their work. Although China has risen in the "citation" rankings, its performance on this measure lags behind its investment and publication rate.