Top 20 institutions in chemistry based on citations per paper

	Country/Territory	Papers	Citations	Impact
1	Scripps Research Institute, US	2,178	71,251	32.71
2	Harvard University, US	2,773	90,094	32.49
3	California Institute of Technology, US	2,217	70,748	31.91
4	Yale University, US	1,766	53,603	30.35
5	Massachusetts Institute of Technology, US	3,734	99,650	26.69
6	Northwestern University, US	2,888	74,379	25.75
7	University of California, Berkeley, US	5,1	1,846	24.25
8	University of California, Santa Barbara, US	2,225	50,948	22.90
9	Stanford University, US	2,729	62,003	22.72
10	University of Utrecht, The Netherlands	2,469	50,244	20.35
11	University of Strasbourg 1, France	3,553	70,108	19.73
12	University of Minnesota, US	3,693	67,403	18.25
13	University of Texas at Austin, US	3,241	57,200	17.65
14	University of Illinois, US	4,486	76,533	17.06
15	University of Wisconsin, US	3,553	60,6	16.96
16	ETH Zurich, Switzerland	4,900	82,264	16.79
17	Max Planck Society, Germany	11,765	184,643	15.69
18	Imperial College London, UK	3,591	56,129	15.63
19	University of Cambridge, UK	4,849	75,741	15.62
20	Technical University of Munich, Germany	3,561	55,546	15.60

This analysis of chemistry's heavy hitters reveals a strong performance by US institutions, which take the first nine ranks and 13 of 20 in all. German institutions hold three spots, while UK universities account for two. One French and one Swiss institution appear.

The data above were extracted from Thomson Scientific's Essential Science Indicators database. This database, currently covering the period January 1997 to December 2007, surveys only journal articles (original research reports and review articles) indexed by Thomson Scientific. Articles are assigned to a category based on the journals in which they were published and Thomson Scientific's journal-to-category field definition scheme. Both articles tabulated and citation counts to those articles are for the period indicated. Naturally, institutions publishing large numbers of papers have a greater likelihood of collecting more citations than scientists publishing fewer papers. This ranking is by citations per paper (impact), among those institutions that have collected 50,000 or more citations in chemistry. For papers with multiple institutional addresses, each institution receives full, not fractional, citation credit. Essential Science Indicators lists institutions ranked in the top 1 per cent for a field over a given period, based on total citations. For the current version, 858 institutions are listed in the field of chemistry, meaning that a total of 85,800 institutions were reviewed to obtain these results. Of the 858, 36 institutions collected 50,000 or more citations. The ranking by citations per paper (impact) seeks to reveal heavy hitters based on per paper influence, not mere output. For more on Thomson Scientific's Essential Science Indicators, see http://scientific.thomson.com/products/esi.