Top nations in neuroscience and behaviour by citation impact

	Country, ranked by cites per paper	Papers	Citations	Citations per paper	Top papers	% top papers
1	United States	118,501	2,675,940	22.58	2,006	1.7
2	England	23,416	528,750	22.58	397	1.7
3	Switzerland	6,417	132,341	20.62	78	1.2
4	Scotland	3,054	58,246	19.07	38	1.2
5	Canada	18,001	337,473	18.75	203	1.1
6	Sweden	7,033	131,238	18.66	78	1.1
7	Germany	,143	503,080	18.53	290	1.1
8	Belgium	3,542	63,696	17.98	37	1.0
9	Austria	2,864	51,329	17.92	30	1.0
10	France	16,9	285,434	17.53	148	0.9
11	Israel	4,081	71,172	17.44	32	0.8
12	Finland	3,199	55,026	17.20	34	1.1
13	Denmark	2,863	48,009	16.77	23	0.8
14	The Netherlands	8,925	147,601	16.54	79	0.9
15	Australia	7,368	111,406	15.12	49	0.7
16	Italy	17,251	244,386	14.17	123	0.7
17	Spain	8,704	119,4	13.70	65	0.7
18	Japan	24,259	322,507	13.29	110	0.5
19	China	6,1	48,948	7.81	16	0.3
20	Brazil	6,158	43,828	7.12	10	0.2

The data above were extracted from the Essential Science Indicators database of Thomson Reuters. This data­base, currently covering the period January 1999 through February 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 journal-to-category field-definition scheme used by Thomson Reuters. Both articles tabulated and citation counts for those articles are for the period indicated. This ranking in neuroscience and behaviour is by citations per paper – among nations whose papers attracted 40,000 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 neuroscience and behaviour, 82 nations are listed, meaning 164 were surveyed. Twenty nations collected 40,000 or more citations, and all are listed above.

Of interest here is the number and percentage of papers from each nation that were highly cited, defined as those in the top 1 per cent by citations, and analysed in cohorts by year of publication. As is evident by the ranking, the percentage of highly cited papers based on each nation’s total output is highly correlated with the citations per paper (impact) measure. This is not surprising given the skewed nature of citation distributions and the effect that highly cited papers have on the mean. The percentages for Finland (ranked 12th) and (to a lesser extent) for the Netherlands (14th) show that their output of highly cited papers is higher than might be expected.

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