Andersen, Jens Peter

Haustein, Stefanie

    Aalborg UniversitetBootstrapping to evaluate accuracy of citation-based journal indicatorsAndersen, Jens Peter; Haustein, StefaniePublication date:2015Document VersionPeer reviewed versionLink to publication from Aalborg UniversityCitation for published version (APA):Andersen, J. P., & Haustein, S. (2015). Bootstrapping to evaluate accuracy of citation-based journal indicators.Poster session presented at 15th International Society of Scientometrics and Informetrics Conference (ISSI2015), Istanbul, Turkey.General rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright ownersand it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.            ? Users may download and print one copy of any publication from the public portal for the purpose of private study or research.            ? You may not further distribute the material or use it for any profit-making activity or commercial gain            ? You may freely distribute the URL identifying the publication in the public portal ?Take down policyIf you believe that this document breaches copyright please contact us at vbn@aub.aau.dk providing details, and we will remove access tothe work immediately and investigate your claim.Downloaded from vbn.aau.dk on: April 29, 2017Bootstrapping to evaluate accuracy of citation-based journal indicatorsMotivationDespite criticism, ranking indicators are in demand. Essential to provide estimates of indicator accuracy, robustness, stability and confidence. This study uses bootstrapping to test the stability of citation -based journal indicators - recent as well as traditional.DataAll clinical medicine records in WoS 2012:34 NSF specialties -> 2,699 journals -> 362,556 records.2-year citation windowc = raw citationss = relative citations (specialty standardised)Indicatorsμc and μs    mean raw and relative citations per paper.Mc and Ms   median raw and relative citations per paper.ND10 and NSD10  top decile ratio of raw and relative citations.MethodsBootstrapping: Each sample (journal) is resampled 1,000 times, allowing calculation of stability data (95% confidence intervals).Standardised (mean normalised) indicator scores used for comparison.ResultsSee figure- and table-legends.Further researchAdditional indicators and specialty variations.Jens Peter Andersen Medical Library, Aalborg University Hospital, Aalborg, Denmark Email: jepea@rn.dk Twitter: @ipogaStefanie Haustein École de bibliothéconomie et des sciences de l’information, Université de Montréal, Montréal, Canada Email: stefanie.haustein@umontreal.ca Twitter: @stefhaustein&NSD10ND10Mcµc µSMSStandardised indicator scoresStandard deviationFigure 2: Standard deviation of standardised indicator scores per journal. Result: Percentile-based indicators outperform mean- and me-dian-based indicators with respect to stability. Median-based in-dicators perform worse than mean-based.Figure 1: Mean raw citations per journal (data points) and bootstrapped stability intervals for dentistry journals. Result: Bootstrapping identifies outlying scores. Stability inter-vals show the effect individual papers have on journal perfor-mance.All ≥50Raw StandardisedIndicator mean SD mean SD mean SDμc 2.321 3.897 1.000 1.679 1.052 1.261Mc 1.477 2.278 1.000 1.543 1.079 1.471μs .835 1.107 1.000 1.326 1.053 1.076Ms .520 .717 1.000 1.381 1.075 1.297ND10 .081 .131 1.000 1.625 1.107 1.640NSD10 .078 .119 1.000 1.536 1.090 1.513Table 1: Mean indicator values and standard deviations for all journals (“All”) and journals publishing 50 or more papers (“≥50”).  Result: All indicators are sensitive to sample sizes. N<50 jour-nals have larger variance than N>50 journals.

Bootstrapping to evaluate accuracy of citation-based journal indicators

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Bootstrapping to evaluate accuracy of citation-based journal indicators

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