Top countries in space sciences

8 October 2009

The data above were extracted from the Essential Science Indicators database of Thomson Reuters. This database, currently covering the period January 1999 through June 2009, surveys only journal articles (original research reports and review articles) indexed by Thomson Reuters. Articles are assigned to a category based on the journals in which they were published and the Thomson Reuters journal-to-category field-definition scheme. Both articles tabulated and citation counts to those articles are for the period indicated. Here our ranking in space sciences, including astronomy and astrophysics, is by citations per paper among nations that collected 25,000 or more citations during the period to reveal weighted impact. For articles with multiple authors from different nations, each nation receives full, not fractional, citation credit. Essential Science Indicators lists nations ranked in the top 50 per cent for a field over a given period, based on total citations. In space sciences, 69 nations are listed, meaning 138 were surveyed. Twenty nations collected at least 25,000 citations in this field during the period. For more information on Thomson Reuters Essential Science Indicators, see http://scientific.thomsonreuters.com/products/esi