JOI 2010 (forthcoming)

References:

Zitt M. Citing-side normalization of journal impact: a robust variant of the Audience Factor (forthcoming in Journal of Informetrics, 2010) PDF

Keywords:

AUDIENCE FACTOR, IMPACT FACTOR, NORMALIZED IMPACT, CITING-SIDE NORMALIZATION, SOURCE NORMALIZATION, JOURNAL IMPACT

Abstract:

The principle of a new type of impact measure was introduced recently, called the "audience factor" (AF). It is a variant of the journal impact factor where emitted citations are weighted inversely to the propensity to cite of the source. In the initial design, propensity was calculated using the average length of bibliography at the source level with two options: a journal-level average or a field-level average. This citing-side normalization controls for propensity to cite, the main determinant of impact factor variability across fields. The AF maintains the variability due to exports-imports of citations across field and to growth differences.   It does not account for influence chains, powerful approaches taken in the wake of Pinski-Narin's influence weights. Here we introduce a robust variant of the audience factor, trying to combine the respective advantages of the two options for calculating bibliography lengths: the classification-free scheme when the bibliography length is calculated at the individual journal level, and the robustness and avoidance of ad-hoc settings when the bibliography length is averaged at the field level. The variant proposed relies on the relative neighborhood of a citing journal, regarded as its micro-field and assumed to reflect the citation behavior in this area of science. The methodology adopted allows a large range of variation of the neighborhood, depending on the local citation network, and partly alleviates the "cross-scale" normalization issue. Citing-side normalization is a general principle which may be extended to other citation counts.

http://www.elsevier.com/wps/find/journaldescription.cws_home/709551/description#description

PDF

JASIST 2008

References :

Zitt M. and Small H. (2008). Modifying the Journal Impact Factor by Fractional Citation Weighting: the Audience Factor, Journal of the American Society for Information Science and Technology vol 59, n°11, pp. 1856-1860. PDF
JEL: A 140

Keywords:

SCHOLARLY JOURNALS, JOURNAL EVALUATION, IMPACT FACTOR, INFLUENCE FACTOR, INFLUENCE WEIGHT, NORMALIZED IMPACT

Abstract:

A new approach to the field normalization of the classical journal impact factor is introduced. This approach, called the audience factor, takes into consideration the citing propensity of journals for a given cited journal, specifically, the mean number of references of each citing journal, and fractionally weights the citations from those citing journals. Hence, the audience factor is a variant of a fractional citation-counting scheme, but computed on the citing journal rather than the citing article or disciplinary level, and, in contrast to other cited-side normalization strategies, is focused on the behavior of the citing entities. A comparison with standard journal impact factors from Thomson Reuters shows a more diverse representation of fields within various quintiles of impact, significant movement in rankings for a number of individual journals, but nevertheless a high overall correlation with standard impact factors.

http://www3.interscience.wiley.com/journal/119882546/abstract

PDF

To top

Scientometrics 2005

References :

Zitt M., Ramanana-Rahary S. and Bassecoulard E. (2005). Relativity of citation performance and excellence measures: from cross-field to cross-scale effects of field-normalisation, Scientometrics, vol 63, n°2, pp. 373-401. PDF
JEL: A 140

Keywords :

EXCELLENCE MEASURES; CITATION ANALYSIS; NORMALISATION; SCIENTIFIC RESEARCH; ORDERED STRUCTURE; RANDOM STRUCTURE ; BIBLIOMETRICS; SCIENCE CITATION INDEX; IMPACT FACTOR; RELATIVE IMPACT; SCIENTIFIC SPECIALTIES; CLASSIFICATION OF SCIENCE; ORDINAL METHODS; OBSERVATION LEVEL

Abstract:

As citation practices strongly depend on fields, field normalisation is recognised as necessary for fair comparison of figures in bibliometrics and evaluation studies. However fields may be defined at various levels, from small research areas to broad academic disciplines, and thus normalisation values are expected to vary. The aim of this project was to test the stability of citation ratings of articles as the level of observation --- hence the basis of normalisation --- changes. The study was conducted on articles in the full SCI range, for publication year 1998 with a 4-year citation window.
Citation ratings have been observed at the five embedded levels of a realistic structure of the scientific production based on ISI subject categories and their aggregates at various scales: all science, large academic discipline, sub-discipline, speciality and journal. Correlations on this empirical set have been benchmarked against two fictitious sets keeping the embedded aggregates of articles, with a redistribution of citation figures to emulate either a totally ordered or a random structure of science, expected to give a "worst case" and a "best case" for the stability of normalised citation indicators
Among various normalisation methods, we selected a simple ranking method (quantiles), based on the citation score of the article in each particular aggregate (journal, speciality, etc.) it belonged to at each level. The results show that: (a) the average citation rankings of articles substantially change with the level of observation (b) observation at the journal level is very particular, the results differ greatly in all test circumstances from all the other levels of observation. The comparison of the emirical set (c) the lack of cross-scale stability is confirmed when looking at the distribution of individual trajectories of articles across the levels; (d) when considering the top-cited fractions, a standard measure of excellence, it is found that the contents of the 'top-cited' set is completely dependent on the level of observation. The instability of impact measures should not be interpreted in terms of lack of robustness but rather as the co-existence of various perspectives each having their own form of legitimacy. A follow-up study will focus on the micro levels of observation and will be based on a structure built around bibliometric groupings rather than conventional groupings based on ISI subject categories.

http://www.springerlink.com/content/t241m8j775474l13/?p=9bd74a0473ea4b3b979490f8ed30e088&pi=25

PDF

 

Back to top

To top