The University of Groningen Ranking of Research Universities

• Global top 100 all fields (table)
• European top 20 (table) 
• Position University of Groningen per field (table)
• Global position of the University of Groningen per ESI field (explanation)

Rationale

There is a growing number of international university rankings and ranking methodologies. Most of these are partly based on the ISI Web of Science database, combined with other indicators such as scientific awards, publications in Nature and Science (Shanghai ranking), or peer and recruiter opinion, proportion of international students and faculty (Times Higher Education ranking). These rankings might be interpreted to reflect the research quality of the institutions. However, peer and recruiter opinion are largely determined by a university’s (or its city’s) reputation. Non existing programs at well known universities are known to have received high peer rankings and universities without any significant research output appear in these rankings. On the other hand, a number of strong research universities are not represented in the Times Higher Education rankings for unclear reasons.

The University of Groningen Ranking  is based exclusively on relative citation impact (Citations per Paper, CPP), which is generally considered to be one of the most objective indicators of research quality. Moreover, it is derived directly from the world’s largest and most used citation database, ISI Web of Science, using Thomson Reuters’ Essential Science Indicators to compare the output and citation impact at the aggregation level of entire institutions, including most larger research universities.

Methodology

• Data were taken directly from Essential Science Indicators (July 2008).
• Institutions with at least 20,000 publications over the past 10.5 years were selected in order to obtain the world’s Top-100 most productive universities.
• Ranking was based on Citations/Paper as an indicator of quality.
• Eighteen non-university institutions like NCI, the Max Planck Society, JST and NASA were excluded from the list.

Geographic distribution

More than half of the top 100 research universities are located in the United States. 31 European universities are represented (the United Kingdom 8, the Netherlands 4, Italy 4, Sweden 3, Germany 3, France 2, Switzerland 2 and Finland, Denmark, Austria, and Belgium each 1). Japan is represented by 7 universities, Canada by 4, Australia by 3, Israel by 2, and Korea and Singapore each by 1.

European Top-20

For the 20 large European universities with highest relative citation impact, CPP is also calculated for the last 5 years only (2004-2008) and compared to the CPP obtained for ESI’s default 10-year period (1998-2008). Relative impact of the more recent publications shows some interesting shifts in ranks. Cambridge, Imperial College, Heidelberg, ETH, both Munich institutes and Groningen all move one to several places up in the ranking, whereas the relative impact of Oxford, Amsterdam, Helsinki, Kings College, Utrecht, Lund and Uppsala tends to decrease.
> European Top-20

Global position of the University of Groningen per ESI Field

Virtually all University Rankings are based on a single overall average mark and do not do justice to the wide degree of diversity within the research world. For medical and scientific disciplines, where articles in international, peer-reviewed journals are the dominant publication type, a much more nuanced picture can be gained on the basis of relative citation impact within well defined, comparable scientific disciplines. With the help of an easy online analysis tool, the Essential Science Indicators (ESI), [1] the number of publications (P) and citations (C) in 22 disciplines (so-called ESI Fields) of any research institution in the world can be compared and the quotient determined (Citations per Publication, CPP). CPP is generally regarded as one of the most objective, quantitative indicators of research quality in these disciplines.

The position per field table  shows the results of an ESI analysis conducted in December 2007. It reveals that the University of Groningen is in the top 4% of the best research institutions in the world in two disciplines: Chemistry and Materials Science. Our position in the global Top-10 in Materials Science was recently confirmed by the Times Higher Education (see THE). In four other disciplines (Plant & Animal Science, Environment/Ecology, Microbiology and Physics) as well as overall ('All Fields'), Groningen is among the global Top 15-33%. Its CPP is also well above average for Geosciences and Space Science, but here, Groningen is too small to determine reliable global ranking figures. [2]

Methodology and further details

The analysis was conducted in December 2007 using the Essential Science Indicators of the ISI Web of Knowledge when ESI covered the period from 1 January 1997 up to and including 31 August 2007.

Via the Institutions menu of this online tool, every research institution that appears in the Web of Science database of Thomson Reuters and achieves the citation threshold [3] in a Field (see Table below) can determine the total number of publications (P), citations (C) and citations per publication (CPP) in the Web of Science in each of 22 broad Fields.

Thus the indicators in columns 2-4 of the position per field table were found by searching for the name ‘univ groningen’ in the institutions menu. The University of Groningen exceeds the citation threshold in 17 Fields. The University of Groningen is not represented or is 'too small’ to pass the ESI threshold in Agricultural Sciences, Computer Science, Immunology, Mathematics and Multidisciplinary.

Although the ESI already uses citation thresholds, a ranking based on CPP still results in extreme CCP values for institutions with low productivity. For example, the Top 20 in Clinical Medicine consists entirely of institutions with a production (averaged over >10 years) of only 1-17 publications and an average CPP of 213-3457 (as against a global average CPP of 9). This is the result of the extremely skewed distribution of citations over publications and the statistical fact that the greater the share of a unit in global production, the more CPP approaches the global average. A fair comparison of CPP thus requires institutes with a low productivity to be excluded.

To this end, ranking lists were first generated ranking lists based on P to determine the total number of institutions that achieve the citation threshold (column 3 in Table below). Next, the P, C and CPP values for the top 50% (based on P) were copied to a spreadsheet in order to calculate the world ranks based on P, C and CPP (columns 5-7 in the position per field table ).

The University of Groningen is too small (in terms of P) in four ESI fields (Space Science, Molecular Biology & Genetics, Economics & Business and Geosciences) to make the top 50%, which is why no ranking positions have been calculated for these fields.

Ranking positions were not calculated either for three other Fields (Neurosciences & Behavior, Psychiatry/Psychology and Social Sciences General), where Web of Science coverage is highly incomplete – which also applies to most of the Arts & Humanities and to the Social Sciences disciplines.

The far right column of the position per field table (% CPP) expresses the University of Groningen ranks as percentage of the number of institutions belonging to the top 50% (No. Top50%, 4^th column of Table below). This shows that in addition to the excellent position in Chemistry and Materials Science (Top 4%) and the good position in Plant & Animal Science, Environment/Ecology, Microbiology and Physics (Top 15-33%), the University of Groningen is also above average in the other fields (Top 46-51%).

 

Table: citation thresholds (column 2) and Number of Institutions (column 3) included in the ESI for each of the 22 Fields and aggregated over all Fields. No. Top 50% (column 4) is the total number of institutions (column 3) divided by 2, with the exception of All Fields where the selection is limited to the top 600 institutions (c. 17%) due to the lack of a citation threshold. CPP Top 50% (column 5) is the average CPP calculated for the top 50% of institutions (based on P). CPP world av. (column 6) is the global average CPP for all publications in the Web of Science for the period 1997-2007 (as of Nov. 2007).

[1] The ESI is one of the purchasable parts of the ISI Web of Knowledge, based on the Web of Science, a global database of publications and citations maintained by the American publisher Thomson Scientific.

[2] It is relatively easy for smaller institutes, i.e. with a small share in the global production of publications, to realise a high CPP as a result of the highly-skewed distribution of citations over publications. This is why this analysis only compares the citation statistics of the larger institutions (in terms of productivity).

[3] The citation thresholds per Field are designed in such a way that only the top 1% of the most cited institutions are included in the ESI rankings. See http://sciencewatch.com/about/met/thresholds (subscription required) for a more detailed explanation and the actual values.