June 22, 2010

Impact Factor Boxing 2010

Golden Gloves Prelim Bouts by Kate Gardiner[This post is part of an ongoing series about impact factors. See this post for the latest impact factors published in 2012.]

Roll up, roll up, ladies and gentlemen, Impact Factor Boxing is here again. As with last year (2009), the metrics used in this combat sport are already a year out of date. But this doesn’t stop many people from writing about impact factors and it’s been an interesting year [1] for the metrics used by many to judge the relative value of scientific work. The Public Library of Science (PLoS) launched their article level metrics within the last year following the example of BioMedCentral’s “most viewed” articles feature. Next to these new style metrics, the traditional impact factors live on, despite their limitations. Critics like Harold Varmus have recently pointed out that (quote):

“The impact factor is a completely flawed metric and it’s a source of a lot of unhappiness in the scientific community. Evaluating someone’s scientific productivity by looking at the number of papers they published in journals with impact factors over a certain level is poisonous to the system. A couple of folks are acting as gatekeepers to the distribution of information, and this is a very bad system. It really slows progress by keeping ideas and experiments out of the public domain until reviewers have been satisfied and authors are allowed to get their paper into the journal that they feel will advance their career.”

To be fair though, it’s not the metric that is flawed, more the way it is used (and abused) – a subject covered in much detail in a special issue of Nature at http://nature.com/metrics [2,3,4,5]. It’s much harder than it should be to get hold of these metrics, so I’ve reproduced some data below (fair use? I don’t know I am not a lawyer…) to minimise the considerable frustrations of using Journal Citation Reports (JCR).

Love them, loathe them, use them, abuse them, ignore them or obsess over them … here’s a small selection of the 7347 journals that are tracked in JCR  ordered by increasing impact.

Journal Title 2009 data from isiknowledge.com/JCR Eigenfactor™ Metrics
Total Cites Impact Factor 5-Year Impact Factor Immediacy Index Articles Cited Half-life Eigenfactor™  Score Article Influence™ Score
RSC Integrative Biology 34 0.596 57 0.00000
Communications of the ACM 13853 2.346 3.050 0.350 177 >10.0 0.01411 0.866
IEEE Intelligent Systems 2214 3.144 3.594 0.333 33 6.5 0.00447 0.763
Journal of Web Semantics 651 3.412 0.107 28 4.6 0.00222
BMC Bionformatics 10850 3.428 4.108 0.581 651 3.4 0.07335 1.516
Journal of Molecular Biology 69710 3.871 4.303 0.993 916 9.2 0.21679 2.051
Journal of Chemical Information and Modeling 8973 3.882 3.631 0.695 266 5.9 0.01943 0.772
Journal of the American Medical Informatics Association (JAMIA) 4183 3.974 5.199 0.705 105 5.7 0.01366 1.585
PLoS ONE 20466 4.351 4.383 0.582 4263 1.7 0.16373 1.918
OUP Bioinformatics 36932 4.926 6.271 0.733 677 5.2 0.16661 2.370
Biochemical Journal 50632 5.155 4.365 1.262 455 >10.0 0.10896 1.787
BMC Biology 1152 5.636 0.702 84 2.7 0.00997
PLoS Computational Biology 4674 5.759 6.429 0.786 365 2.5 0.04369 3.080
Genome Biology 12688 6.626 7.593 1.075 186 4.8 0.08005 3.586
Trends in Biotechnology 8118 6.909 8.588 1.407 81 6.4 0.02402 2.665
Briefings in Bioinformatics 2898 7.329 16.146 1.109 55 5.3 0.01928 5.887
Nucleic Acids Research 95799 7.479 7.279 1.635 1070 6.5 0.37108 2.963
PNAS 451386 9.432 10.312 1.805 3765 7.6 1.68111 4.857
PLoS Biology 15699 12.916 14.798 2.692 195 3.5 0.17630 8.623
Nature Biotechnology 31564 29.495 27.620 5.408 103 5.7 0.14503 11.803
Science 444643 29.747 31.052 6.531 897 8.8 1.52580 16.570
Cell 153972 31.152 32.628 6.825 359 8.7 0.70117 20.150
Nature 483039 34.480 32.906 8.209 866 8.9 1.74951 18.054
New England Journal of Medicine 216752 47.050 51.410 14.557 352 7.5 0.67401 19.870

Maybe next year Thomson Reuters, who publish this data, could start attaching large government health warnings (like on cigarette packets) and long disclaimers to this data? WARNING: Abusing these figures can seriously damage your Science – you have been warned!


  1. Rizkallah, J., & Sin, D. (2010). Integrative Approach to Quality Assessment of Medical Journals Using Impact Factor, Eigenfactor, and Article Influence Scores PLoS ONE, 5 (4) DOI: 10.1371/journal.pone.0010204
  2. Abbott, A., Cyranoski, D., Jones, N., Maher, B., Schiermeier, Q., & Van Noorden, R. (2010). Metrics: Do metrics matter? Nature, 465 (7300), 860-862 DOI: 10.1038/465860a
  3. Van Noorden, R. (2010). Metrics: A profusion of measures Nature, 465 (7300), 864-866 DOI: 10.1038/465864a
  4. Braun, T., Osterloh, M., West, J., Rohn, J., Pendlebury, D., Bergstrom, C., & Frey, B. (2010). How to improve the use of metrics Nature, 465 (7300), 870-872 DOI: 10.1038/465870a
  5. Lane, J. (2010). Let’s make science metrics more scientific Nature, 464 (7288), 488-489 DOI: 10.1038/464488a

[Creative Commons licensed picture of Golden Gloves Prelim Bouts by Kate Gardiner ]

July 24, 2009

Escape from the impact factor: The Great Escape?

The Great Escape with Steve McQueenQuite by chance, I stumbled on this interesting paper [1] yesterday by Philip Campbell who is the Editor-in-Chief of the scientific über-journal Nature [2]. Here is the abstract:

As Editor-in-Chief of the journal Nature, I am concerned by the tendency within academic administrations to focus on a journal’s impact factor when judging the worth of scientific contributions by researchers, affecting promotions, recruitment and, in some countries, financial bonuses for each paper. Our own internal research demonstrates how a high journal impact factor can be the skewed result of many citations of a few papers rather than the average level of the majority, reducing its value as an objective measure of an individual paper. Proposed alternative indices have their own drawbacks. Many researchers say that their important work has been published in low-impact journals. Focusing on the citations of individual papers is a more reliable indicator of an individual’s impact. A positive development is the increasing ability to track the contributions of individuals by means of author-contribution statements and perhaps, in the future, citability of components of papers rather than the whole. There are attempts to escape the hierarchy of high-impact-factor journals by means of undifferentiated databases of peer-reviewed papers such as PLoS One. It remains to be seen whether that model will help outstanding work to rise to due recognition regardless of editorial selectivity. Although the current system may be effective at measuring merit on national and institutional scales, the most effective and fair analysis of a person’s contribution derives from a direct assessment of individual papers, regardless of where they were published.

It’s well worth reading the views of the editor of an important closed-access journal like Nature, a world champion heavyweight of Impact Factor Boxing. So their view on article-level bibliometrics and novel models of scientific publishing on the Web like PLoS ONE is enlightening. There are some interesting papers in the same issue, which has a special theme on the use and misuse of bibliometric indices in evaluating scholarly performance. Oh, and the article is published in an Open Access Journal too. Is it just me, or is there a strong smell of irony in here?


  1. Philip Campbell (2008). Escape from the impact factor Ethics in Science and Environmental Politics, 8, 5-7 DOI: 10.3354/esep00078
  2. Philip Campbell (1995). Postscript from a new hand Nature, 378 (6558), 649-649 DOI: 10.1038/378649b0
  3. John Sturges (1963) The Great Escape

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