significance test of differences among ranks in the SCImago Institutions Rankings 2011

Loet Leydesdorff loet at LEYDESDORFF.NET
Wed Oct 12 02:24:21 EDT 2011

The new Excellence Indicator in the World Report of the SCImago Institutions
Rankings 2011 <> 

Lutz Bornmann,[1] <>  Felix de
Moya-Anegón,[2] <>  and Loet
Leydesdorff [3] <> 

 <> z-test for
significance testing of ranks and differences among ranksDescription:

The new excellence indicator in the World Report of the SCImago Institutions
Rankings (SIR) makes it possible to test differences in the ranking in terms
of statistical significance. For example, at the 17th position of these
rankings, UCLA has an output of 37,994 papers with an excellence indicator
of 28.9. Stanford University follows at the 19th position with 37,885 papers
and 29.1 excellence, and z = - 0.607. The difference between these two
institution thus is not statistically significant. We provide a calculator
at in which one can fill
out this test for any two institutions, and also for each institution on
whether its score is significantly above or below expectation (assuming that
10% of the papers are for stochastic reasons in the top-10% set). 



 <> [1] Max Planck Society,
Administrative Headquarters, Hofgartenstr. 8, 80539 Munich, Germany.

 <> [2] CSIC/CCHS/IPP,
Albasanz 26 Madrid, Spain.

 <> [3] Amsterdam School of
Communication Research, University of Amsterdam, Kloveniersburgwal 48,
NL-1012 CX, Amsterdam, The Netherlands.


** apologies for cross-postings

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