Top nations in computer science

	Country	Papers	Citations	Citations per paper
1	Sweden	3,207	21,675	6.76
2	United States	70,638	374,292	5.30
3	Israel	4,364	20,500	4.70
4	Denmark	2,096	9,510	4.54
5	Switzerland	4,006	17,898	4.47
6	England	15,919	62,960	3.96
7	Scotland	2,182	8,037	3.68
8	Canada	11,584	41,135	3.55
9	Australia	6,654	22,763	3.42
10	Norway	1,542	5,181	3.36
11	Belgium	3,344	11,080	3.31
12	The Netherlands	5,867	19,368	3.30
13	France	14,731	47,469	3.22
14	Germany	18,982	60,956	3.21
15	Italy	11,531	34,085	2.96
16	Singapore	3,788	10,649	2.81
17	Austria	2,774	7,625	2.75
18	Finland	2,583	6,783	2.63
19	Japan	14,714	37,958	2.58
20	India	3,979	9,838	2.47

The data above were extracted from the Essential Science Indicators database of Thomson Reuters. This database, currently covering the period January 1999 to 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 is by citations per paper among nations that collected 5,000 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 computer sciences, 79 nations are listed, meaning 158 were surveyed. Twenty-seven nations collected at least 5,000 citations in this field during the period covered.

For more information on Thomson Reuters Essential Science Indicators, see http://scientific.thomsonreuters. com/products/esi