Top institutions in physics by impact

	Scientist	Papers	Citations	Citations per paper
1	IBM Corporation Global	2,372	58,086	24.49
2	Boston University USA	2,399	56,652	23.61
3	University of Pennsylvania USA	2,246	52,163	23.22
4	Harvard University USA	4,045	88,605	21.90
5	Stanford University USA	5,330	114,965	21.57
6	University of California, Santa Barbara USA	4,660	99,081	21.26
7	Cornell University USA	3,131	66,340	21.19
8	University of Washington USA	3,077	64,886	21.09
9	Caltech USA	4,193	88,325	21.06
10	Princeton University USA	5,094	104,574	20.53
11	Brookhaven National Laboratory USA	4,098	83,623	20.41
12	Massachusetts Institute of Technology USA	7,602	150,715	19.83
13	University of Minnesota USA	2,705	51,846	19.17
14	University of California, Berkeley USA	7,226	129,223	17.88
15	Cern Switzerland	6,323	109,121	17.26
16	University of California, San Diego USA	4,249	71,428	16.81
17	Ohio State University USA	3,141	52,668	16.77
18	National Inst of Standards and Technology USA	4,004	64,046	16.00
19	Argonne National Laboratory USA	5,325	83,313	15.65
20	University of California, Los Angeles USA	4,222	65,246	15.45

This analysis reveals a strong per paper performance by US institutions, which take 18 of the first 20 ranks. IBM is considered a multinational entity; Cern is the other institution represented in the top 20. 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, 629 institutions are listed in the field of physics, meaning that a total of 62,900 institutions were reviewed to obtain these results. Of the 629, 49 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.

The data above were extracted from Thomson Scientific’s Essential Science Indicators database. This database, currently covering the period January 1998 to February 2008, 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 those publishing fewer papers. This ranking is by citations per paper (impact), among those institutions that have collected 50,000 or more citations in physics. For papers with multiple institutional addresses, each institution receives full, not fractional, citation credit.

For more information on Thomson Scientific’s Essential Science Indicators, see http://scientific.thomson.com/products/esi. Also see: http://scientific.thomson.com.