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What is Impact? How do you measure it? . Wouter Gerritsma. Programme. Publishing Journals Citations Impact Journal impact Publishing strategy. What is impact?. I have published in Nature My report has been used by the government I've been cited 22 times
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What is Impact?How do you measure it? Wouter Gerritsma
Programme • Publishing • Journals • Citations • Impact • Journal impact • Publishing strategy
What is impact? • I have published in Nature • My report has been usedby the government • I've been cited 22 times • My article has downloaded 2421 times • I was invitedto the late nightnews • I filed a patent over myinvention
Citation enhanced A&I databases • Web of Science • Scopus • Google Scholar (http://scholar.google.com) • PsychInfo, SciFinder (A&I databases in Digital Library) • ArXiv (Physics) • Spires (high energy physics) • Citeseer (ICT) • Other OA Initiatives
Web of Science • Search: • Articles are found based on Authors, Addresses, etc. • For each article Times cited is presented • Cited reference search: • Searches in the reference lists of records • Not all of your articles are found. Non-cited articles are missing
How do we compare numbers • Scientist Z. Math has a publication from 2001 with 17 citations • Scientist M. Biology has a publication from 2009 with 24 citations
Bibliometric indicators: An example • Kroes-Nijboer, A; Venema, P; Bouman, J; van der Linden, E (2009) The Critical Aggregation Concentration of beta-Lactoglobulin-Based Fibril Formation. Food Biophysics 4(2):59-63. • Citations from WoS: 10 • Journal: Food Biophysics • Categorised by ESI in Agricultural Sciences • Baseline data for Agricultural Science. • Article from 2009 in Agricultural Sciences: • On average: 4.25 citations; top 10%: 11citations; top1%: 26 citations • Relative Impact: 10/4.25 = 2.35 Values Oct. 2012
Essential Science Indicators • Analytical database, covering 10 years + current year building • Comparisons between Countries, Institutes, Scientists and Journals • Hot papers / Highly cited papers • Research fronts • Baselines
Steps in a citation analysis • Look up the citation data (Web of Science) • Matching Journal(s) with appropriate research fields(Essential Science Indicators) • Collect baseline data (Essential Science Indicators) • Calculate the relative impact
Interpretation of RI for small groups • With 10-50 publications per year RI ≤ 0.8 : below world average impact 0.8 < RI ≤ 1.2 : world average impact 1.2 < RI ≤ 2.0 : above world average impact 2.0 < RI ≤ 3.0 : very good average impact RI > 3.0 : excellent average impact
H-index • Balance between productivity and citedness • To rule out the effect of one or two highly cited papers • Applicable to authors, journals, research groups, compounds, subjects etc. • But there are some serious doubts about robustness Waltman, L. & N. J. van Eck (2011). The inconsistency of the h-index. Journal of the American Society for Information Science and Technology 63(2):406-415 http://dx.doi.org/10.1002/asi.21678
Journal Performance Indicators • Journal performance indicators are based on citations to articles • Journal Citation Reports (JCR) • a.o. standard Journal Impact Factors and 5-year Impact Factors • Scopus Journal Analyzer (SJA) • a.o. SCImago Journal Rank (SJR) and Source Normalized Impact per Paper (SNIP) • Also available on http://journalmetrics.com/
Journal Citation Reports (JCR) Reports three measures • Impact factor • Immediacy Index • Cited half life Adapted from: Amin, M and Mabe, M. (2000) Impact factors: use and abuse. Perspectives in Publishing, No. 1, 6 pp. http://www.elsevier.com/framework_editors/pdfs/Perspectives1.pdf
Selecting journals on the basis of IF • Word of warning • Our opinion: Be careful when using Journal Impact factors to judge the performance of a group or individual scientist • Used for NWO grant applications and Tenure track at Wageningen UR
50% of articles generate 90% of all cites Seglen, P. O. (1997). Why the impact factor of journalsshouldnotbeused for evaluating research. BMJ314(7079): 497-502. http://bmj.bmjjournals.com/cgi/content/full/314/7079/497
Journals from Agricultural Economics & Policy: Quartile Scores Q1 Q2 Q3 Q4 JCR Science Edition 2009
Journal quality and article impact 2003-2009, for Wageningen UR Source: Wageningen Yield, Feb. 2012
Alternatives for Impact Factor • Allbased on Scopus • Scimago Journal Rank (SJR) http://www.scimagojr.com/ • Source Normalized Impact per Paper (SNIP) http://www.journalmetrics.com
Altmetrics • Quickly developing • ScienceCard • Total-Impact • Readermeter • Microsoft Academic Search • etc. Wouters, P. & R. Costas (2012). Users, narcissism and control. Utrecht, NL: SURFfoundation. http://www.surffoundation.nl/ en/publicaties/Pages/Users_narcissism_control.aspx.
Thank you! On the Web: @wowter wowter.net www.slideshare.net/wowter