CiteULike: Tag impactfactor

Journal Status

Johan Bollen — 2006-02-23T08:51:20-00:00

(9 Jan 2006)

The status of an actor in a social context is commonly defined in terms of two factors: the total number of endorsements the actor receives from other actors and the prestige of the endorsing actors. These two factors indicate the distinction between popularity and expert appreciation of the actor, respectively. We refer to the former as popularity and to the latter as prestige. These notions of popularity and prestige also apply to the domain of scholarly assessment. The ISI Impact Factor (ISI IF) is defined as the mean number of citations a journal receives over a 2 year period. By merely counting the amount of citations and disregarding the prestige of the citing journals, the ISI IF is a metric of popularity, not of prestige. We demonstrate how a weighted version of the popular PageRank algorithm can be used to obtain a metric that reflects prestige. We contrast the rankings of journals according to their ISI IF and their weighted PageRank, and we provide an analysis that reveals both significant overlaps and differences. Furthermore, we introduce the Y-factor which is a simple combination of both the ISI IF and the weighted PageRank, and find that the resulting journal rankings correspond well to a general understanding of journal status.

Toward alternative metrics of journal impact: A comparison of download and citation data

Johan Bollen — 2005-08-01T12:26:07-00:00

Information Processing & Management, Vol. 41, No. 6. (December 2005), pp. 1419-1440.

We generated networks of journal relationships from citation and download data, and determined journal impact rankings from these networks using a set of social network centrality metrics. The resulting journal impact rankings were compared to the ISI IF. Results indicate that, although social network metrics and ISI IF rankings deviate moderately for citation-based journal networks, they differ considerably for journal networks derived from download data. We believe the results represent a unique aspect of general journal impact that is not captured by the ISI IF. These results furthermore raise questions regarding the validity of the ISI IF as the sole assessment of journal impact, and suggest the possibility of devising impact metrics based on usage information in general.

Citation Statistics From More Than a Century of Physical Review

S Redner — 2007-02-07T21:59:53-00:00

(6 Oct 2004)

We study the statistics of citations from all Physical Review journals for the 110-year period 1893 until 2003. In addition to characterizing the citation distribution and identifying publications with the highest citation impact, we investigate how citations evolve with time. There is a positive correlation between the number of citations to a paper and the average age of citations. Citations from a publication have an exponentially decaying age distribution; that is, old papers tend to not get cited. In contrast, the citations to a publication are consistent with a power-law age distribution, with an exponent close to -1 over a time range of 2 -- 20 years. We also identify a number of strongly-correlated citation bursts and other dramatic features in the time history of citations to individual publications.

On indexing in the Web of Science and predicting journal impact factor

Xiu-Fang Wu — 2008-07-07T13:56:01-00:00

Journal of Zhejiang University - Science B, Vol. 9, No. 7. (1 July 2008), pp. 582-590.

Abstract We discuss what document types account for the calculation of the journal impact factor (JIF) as published in the Journal Citation Reports (JCR). Based on a brief review of articles discussing how to predict JIFs and taking data differences between the Web of Science (WoS) and the JCR into account, we make our own predictions. Using data by cited-reference searching for Thomson Scientific’s WoS, we predict 2007 impact factors (IFs) for several journals, such as Nature, Science, Learned Publishing and some Library and Information Sciences journals. Based on our colleagues’ experiences we expect our predictions to be lower bounds for the official journal impact factors. We explain why it is useful to derive one’s own journal impact factor.

Distributional differences of the impact factor in the sciences versus the social sciences: An analysis of the probabilistic structure of the 2005 journal citation reports

Stephen Bensman — 2008-06-13T20:34:56-00:00

Journal of the American Society for Information Science and Technology, Vol. 59, No. 9. (2008), pp. 1366-1382.

This paper examines the probability structure of the 2005 Science Citation Index (SCI) and Social Sciences Citation Index (SSCI) Journal Citation Reports (JCR) by analyzing the Impact Factor distributions of their journals. The distribution of the SCI journals corresponded with a distribution generally modeled by the negative binomial distribution, whereas the SSCI distribution fit the Poisson distribution modeling random, rare events. Both Impact Factor distributions were positively skewed - the SCI much more so than the SSCI - indicating excess variance. One of the causes of this excess variance was that the journals highest in the Impact Factor in both JCRs tended to class in subject categories well funded by the National Institutes of Health. The main reason for the SCI Impact Factor distribution being more skewed than the SSCI one was that review journals defining disciplinary paradigms play a much more important role in the sciences than in the social sciences.

Relationship between Quality and Editorial Leadership of Biomedical Research Journals: A Comparative Study of Italian and UK Journals

Valerie Matarese — 2008-07-07T14:05:27-00:00

PLoS ONE, Vol. 3, No. 7. (2 July 2008), e2512.

Background: The quality of biomedical reporting is guided by statements of several organizations. Although not all journals adhere to these guidelines, those that do demonstrate “editorial leadership” in their author community. To investigate a possible relationship between editorial leadership and journal quality, research journals from two European countries, one Anglophone and one non-Anglophone, were studied and compared. Quality was measured on a panel of bibliometric parameters while editorial leadership was evaluated from journals' instructions to authors. Methodology/Principal Findings: The study considered all 76 Italian journals indexed in Medline and 76 randomly chosen UK journals; only journals both edited and published in these countries were studied. Compared to UK journals, Italian journals published fewer papers (median, 60 vs. 93; p = 0.006), less often had online archives (43 vs. 74; p<0.001) and had lower median values of impact factor (1.2 vs. 2.7, p<0.001) and SCImago journal rank (0.09 vs. 0.25, p<0.001). Regarding editorial leadership, Italian journals less frequently required manuscripts to specify competing interests (p<0.001), authors' contributions (p = 0.005), funding (p<0.001), informed consent (p<0.001), ethics committee review (p<0.001). No Italian journal adhered to COPE or the CONSORT and QUOROM statements nor required clinical trial registration, while these characteristics were observed in 15%–43% of UK journals (p<0.001). At multiple regression, editorial leadership predicted 37.1%–49.9% of the variance in journal quality defined by citation statistics (p<0.0001); confounding variables inherent to a cross-cultural comparison had a relatively small contribution, explaining an additional 6.2%–13.8% of the variance. Conclusions/Significance: Journals from Italy scored worse for quality and editorial leadership than did their UK counterparts. Editorial leadership predicted quality for the entire set of journals. Greater appreciation of international initiatives to improve biomedical reporting may help low-quality journals achieve higher status.

The DCI index: Discounted cumulated impact-based research evaluation

Kalervo Järvelin — 2008-06-13T20:27:36-00:00

Journal of the American Society for Information Science and Technology, Vol. 59, No. 9. (2008), pp. 1433-1440.

Research evaluation is increasingly popular and important among research funding bodies and science policy makers. Various indicators have been proposed to evaluate the standing of individual scientists, institutions, journals, or countries. A simple and popular one among the indicators is the h-index, the Hirsch index (Hirsch 2005), which is an indicator for lifetime achievement of a scholar. Several other indicators have been proposed to complement or balance the h-index. However, these indicators have no conception of aging. The AR-index (Jin et al. 2007) incorporates aging but divides the received citation counts by the raw age of the publication. Consequently, the decay of a publication is very steep and insensitive to disciplinary differences. In addition, we believe that a publication becomes outdated only when it is no longer cited, not because of its age. Finally, all indicators treat citations as equally material when one might reasonably think that a citation from a heavily cited publication should weigh more than a citation froma non-cited or little-cited publication.We propose a new indicator, the Discounted Cumulated Impact (DCI) index, which devalues old citations in a smooth way. It rewards an author for receiving new citations even if the publication is old. Further, it allows weighting of the citations by the citation weight of the citing publication. DCI can be used to calculate research performance on the basis of the h-core of a scholar or any other publication data set. Finally, it supports comparing research performance to the average performance in the domain and across domains as well.

Show me the data

Mike Rossner — 2007-12-18T08:22:14-00:00

J. Cell Biol., Vol. 179, No. 6. (17 December 2007), pp. 1091-1092.

10.1083/jcb.200711140

Impact factors: uses and abuses.

J Neuberger — 2007-12-01T15:29:04-00:00

Eur J Gastroenterol Hepatol, Vol. 14, No. 3. (March 2002), pp. 209-211.

Quantitative assessment of the scientific merit of journals and articles is being used increasingly to assess and compare researchers and institutions. The most commonly used measure is the 2 year Impact Factor, which broadly reflects the number of times each article in the journal has been cited over the previous 2 years. There are clear limitations to the use of such measures - not least, Impact Factors reflect the journal not the article, vary with time and correlate only poorly with perceived excellence. Simple comparison of impact factors in different specialties may be misleading. Review journals often have higher Impact Factors than those with original data. Both authors and editors can try to manipulate journal Impact Factors. However, despite valid concerns, Impact Factors are widely used and offer, at present, the best simple tool for comparison of output. Like all measures, the use of Impact Factors has to be tempered with knowledge of their limitations and common sense used in interpreting any data based on any analysis.

Journal impact factor: a brief review.

E Garfield — 2007-12-01T15:24:48-00:00

CMAJ, Vol. 161, No. 8. (19 October 1999), pp. 979-980.

The "impact factor" revisited

Peng Dong — 2005-12-12T21:09:54-00:00

Biomedical Digital Libraries, Vol. 2, No. 1. (05 December 2005), 7.

The number of scientific journals has become so large that individuals, institutions and institutional libraries cannot completely store their content physically, and much less so intellectually. In order to prioritize the choice of quality information sources, librarians and scientists are in need of reliable decision aids. The "impact factor" is the most commonly used assessment aid in the decision-making process of which journals to contribute to, or to retrieve knowledge from. It is also an often misunderstood tool. This narrative review explains how the impact factor is calculated, how bias is introduced into the calculation, which questions it can or cannot answer, and how different professional groups can benefit from the information that the impact factor provides.