Étiquette : Impact Factor

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Non classé

Comparing journals from different fields of Science and…

Comparing journals from different fields of Science and Social Science through a JCR Subject Categories Normalized Impact Factor :

« The journal Impact Factor (IF) is not comparable among fields of Science and Social Science because of systematic differences in publication and citation behaviour across disciplines. In this work, a decomposing of the field aggregate impact factor into five normally distributed variables is presented. Considering these factors, a Principal Component Analysis is employed to find the sources of the variance in the JCR subject categories of Science and Social Science. Although publication and citation behaviour differs largely across disciplines, principal components explain more than 78% of the total variance and the average number of references per paper is not the primary factor explaining the variance in impact factors across categories. The Categories Normalized Impact Factor (CNIF) based on the JCR subject category list is proposed and compared with the IF. This normalization is achieved by considering all the indexing categories of each journal. An empirical application, with one hundred journals in two or more subject categories of economics and business, shows that the gap between rankings is reduced around 32% in the journals analyzed. This gap is obtained as the maximum distance among the ranking percentiles from all categories where each journal is included. »

URL : http://arxiv.org/abs/1304.5107

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Non classé

Deep Impact Unintended consequences of journal rank …

Deep Impact: Unintended consequences of journal rank :

« Much has been said about the increasing bureaucracy in science, stifling innovation, hampering the creativity of researchers and incentivizing misconduct, even outright fraud. Many anecdotes have been recounted, observations described and conclusions drawn about the negative impact of impact assessment on scientists and science. However, few of these accounts have drawn their conclusions from data, and those that have typically relied on a few studies. In this review, we present the most recent and pertinent data on the consequences that our current scholarly communication system has had on various measures of scientific quality (such as utility/citations, methodological soundness, expert ratings and retractions). These data confirm previous suspicions: using journal rank as an assessment tool is bad scientific practice. Moreover, the data lead us to argue that any journal rank (not only the currently-favored Impact Factor) would have this negative impact. Therefore, we suggest that abandoning journals altogether, in favor of a library-based scholarly communication system, will ultimately be necessary. This new system will use modern information technology to vastly improve the filter, sort and discovery function of the current journal system. »

URL : http://arxiv.org/abs/1301.3748

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EN

Rising Publication Delays Inflate Journal Impact Factors

Journal impact factors have become an important criterion to judge the quality of scientific publications over the years, influencing the evaluation of institutions and individual researchers worldwide. However, they are also subject to a number of criticisms.

Here we point out that the calculation of a journal’s impact factor is mainly based on the date of publication of its articles in print form, despite the fact that most journals now make their articles available online before that date.

We analyze 61 neuroscience journals and show that delays between online and print publication of articles increased steadily over the last decade. Importantly, such a practice varies widely among journals, as some of them have no delays, while for others this period is longer than a year.

Using a modified impact factor based on online rather than print publication dates, we demonstrate that online-to-print delays can artificially raise a journal’s impact factor, and that this inflation is greater for longer publication lags.

We also show that correcting the effect of publication delay on impact factors changes journal rankings based on this metric.

We thus suggest that indexing of articles in citation databases and calculation of citation metrics should be based on the date of an article’s online appearance, rather than on that of its publication in print.

URL : http://www.plosone.org/article/info:doi/10.1371/journal.pone.0053374

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Non classé

On the impact of Gold Open Access journals…

On the impact of Gold Open Access journals :

« Gold Open Access (=Open Access publishing) is for many the preferred route to achieve unrestricted and immediate access to research output. However, true Gold Open Access journals are still outnumbered by traditional journals. Moreover availability of Gold OA journals differs from discipline to discipline and often leaves scientists concerned about the impact of these existent titles. This study identified the current set of Gold Open Access journals featuring a Journal Impact Factor (JIF) by means of Ulrichsweb, Directory of Open Access Journals and Journal Citation Reports (JCR). The results were analyzed regarding disciplines, countries, quartiles of the JIF distribution in JCR and publishers. Furthermore the temporal impact evolution was studied for a Top 50 titles list (according to JIF) by means of Journal Impact Factor, SJR and SNIP in the time interval 2000–2010. The identified top Gold Open Access journals proved to be well-established and their impact is generally increasing for all the analyzed indicators. The majority of JCR-indexed OA journals can be assigned to Life Sciences and Medicine. The success-rate for JCR inclusion differs from country to country and is often inversely proportional to the number of national OA journal titles. Compiling a list of JCR-indexed OA journals is a cumbersome task that can only be achieved with non-Thomson Reuters data sources. A corresponding automated feature to produce current lists ‘‘on the fly’’ would be desirable in JCR in order to conveniently track the impact evolution of Gold OA journals. »

URL : https://uscholar.univie.ac.at/view/o:246061

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EN

The weakening relationship between the Impact Factor and papers’ citations in the digital age

Authors : George A. Lozano, Vincent Lariviere, Yves Gingras

Historically, papers have been physically bound to the journal in which they were published but in the electronic age papers are available individually, no longer tied to their respective journals. Hence, papers now can be read and cited based on their own merits, independently of the journal’s physical availability, reputation, or Impact Factor.

We compare the strength of the relationship between journals’ Impact Factors and the actual citations received by their respective papers from 1902 to 2009. Throughout most of the 20th century, papers’ citation rates were increasingly linked to their respective journals’ Impact Factors.

However, since 1990, the advent of the digital age, the strength of the relation between Impact Factors and paper citations has been decreasing. This decrease began sooner in physics, a field that was quicker to make the transition into the electronic domain.

Furthermore, since 1990, the proportion of highly cited papers coming from highly cited journals has been decreasing, and accordingly, the proportion of highly cited papers not coming from highly cited journals has also been increasing.

Should this pattern continue, it might bring an end to the use of the Impact Factor as a way to evaluate the quality of journals, papers and researchers. »

URL : http://arxiv.org/abs/1205.4328

Catégories
FR

Les nouvelles formes d’évaluation scientifique : quelles évolutions en sciences, technique et médecine ?

Dès 1960, l’Institute for Scientific Information (I.S.I.) de Philadelphie, sous l’impulsion d’Eugen Garfield, a mis en œuvre le Science Citation Index (S.C.I) pour l’évaluation des auteurs, suivi en 1975 par le Journal Citation Reports (J.C.R.) pour celle des revues.

Au terme d’une analyse critique de ce modèle, nous envisagerons de nouvelles approches : l’algorithme mis au point sur le site Citebase par les équipes de S.Harnad à Southampton (G.-B.) et T.Brody à Cornell (Ithaca, N.-Y.) sur le miroir britannique d’ArXiv.org. (l’un des plus importants sites mondiaux d’archives ouvertes scientifiques) Scholar Google, avatar du moteur généraliste standard lancé sur le Net en novembre 2004 deux alternatives récentes à la définition d’un facteur d’impact proposées par J.E. Hirsch (facteur h lié à la production individuelle d’un chercheur) et l’équipe de J. Bollen (Journal Status) ; donc sur les Auteurs d’une part et les Sources de l’autre le modèle du  » collectif  » Faculty of 1000 dans les domaines biomédicaux.

Son originalité par rapport aux précédents réside dans le primat de l’évaluation « humaine » qualitative sur le principe statistique de la citation. Après un essai de typologie des comités de lecture et des usages en cours dans les différentes disciplines scientifiques, on conclura sur la nécessité d’explorer rapidement la voie d’un nouvel outil d’évaluation libre d’accès, dont les règles seraient clairement définies, tant au niveau de la couverture qu’à celui des critères d’analyse qualitative et statistique.

URL : http://archivesic.ccsd.cnrs.fr/sic_00260459/fr/

Catégories
FR

L’évaluation des publications scientifiques : nouvelles approches, nouveaux enjeux

Après avoir resitué l’évaluation dans un contexte international (notamment Shanghai) et national (programme P150 de la LOLF), l’étude porte sur une analyse critique du modèle ISI et des modèles alternatifs (Eigenfactor et dérivés du Weighted Page Rank). Elle tente de définir les conditions d’une évaluation plus qualitative en lien avec les Archives ouvertes.

URL : http://archivesic.ccsd.cnrs.fr/sic_00589641/fr/