Comments on the paper of J. M. Campanario: The effect of citations on the significance of decimal places in the computation of journal impact factors

We give mathematical explanations of some empirical results obtained by Campanario in Scientometrics 99(2):289–298, (2014).     

Evaluating journal impact based on weighted citations

Scientometrics - Publishing at high-rank journals is a common objective to most researchers, and there’s a crucial need for a journal ranking system with universal recognition. This paper...     

Characteristics of journal impact factors: The effects of uncitedness and citation distribution on the understanding of journal impact factors

Summary In this study, journal impact factors play a central role. In addition to this important bibliometric indicator, which evolves around the average impact of a journal in a two-year timeframe, related aspects of journal impact measurement are studied. Aspects like the output volume, the percentage of publications not cited, and the citation frequency distribution within a set timeframe are researched, and put in perspective with the 'classical' journal Impact Factor. In this study it is shown that these aspects of journal impact measurement play a significant role, and are strongly inter-related. Especially the separation between journals on the basis of the differences in output volume seems to be relevant, as can be concluded from the different results in the analysis of journal impact factors, the degree of uncitedness, and the share of a journal its contents above or below the impact factor value.     

Behind citing-side normalization of citations: some properties of the journal impact factor

A new family of citation normalization methods appeared recently, in addition to the classical methods of “cited-side” normalization and the iterative measures of intellectual influence in the wake of Pinski and Narin influence weights. These methods have a quite global scope in citation analysis but were first applied to the journal impact, in the experimental Audience Factor (AF) and the Scopus Source-Normalized Impact per Paper (SNIP). Analyzing some properties of the Garfield’s Journal Impact Factor, this note highlights the rationale of citing-side (or source-level, fractional citation, ex ante) normalization.     

Predicting subsequent citations to articles published in twelve crime-psychology journals: Author impact versus journal impact

Summary Four hundred and twenty-eight articles published in 12 crime-psychology journals during the 2003 calendar year were reviewed for subsequent citations in the Social Science Citation Index (SSCI). Fifteen potential predictors were reduced to nine after subjecting the 15 variables to a principal components analysis with varimax rotation. The nine predictors included author characteristics - gender, occupational affiliation (academic-nonacademic), national affiliation (U.S.-other), citations per 2001-2002 first author publications - article characteristics - collaboration (single author-multiple author), article length, reviews, subject matter (corrections/criminology-legal/forensic) - and journal characteristics - journal impact. Negative binomial regression of the citations earned by these 428 journal articles in a 23 to 34 month follow-up (M = 28 months) revealed significant effects for citations per 2001-2002 first author publications, national affiliation, and review articles. These results suggest that author impact may be a more powerful predictor of citations received by a journal article than the periodical in which the article appears.     

The influence of opening up peer review on the citations of journal articles

Scientometrics - This paper studied whether opening up review reports benefits science in terms of citations by taking Nature Communications as an example. To address this question, we collected...     

The reflection of LOTKA's law in the structure of citations of a journal

A complex structure measure for social groups was applied to the structure of citations in a journal. The citation structure reflected LOTKA's law on the various levels of group structure measure. On the first structure level the reciprocal effect of social and cognitive factors became discernible. The different hierarchical levels of the structure measure were a reflection of the logarithm of number of publications per author obtained in a group of authors with a definite number of publications.     

The generalized propensity score methodology for estimating unbiased journal impact factors

The journal impact factor (JIF) proposed by Garfield in the year 1955 is one of the most commonly used and prominent citation-based indicators of the performance and significance of a scientific journal. The JIF is simple, reasonable, clearly defined, and comparable over time and, what is more, can be easily calculated from data provided by Thomson Reuters, but at the expense of serious technical and methodological flaws. The paper discusses one of the core problems: The JIF is affected by bias factors (e.g., document type) that have nothing to do with the prestige or quality of a journal. For solving this problem, we suggest using the generalized propensity score methodology based on the Rubin Causal Model. Citation data for papers of all journals in the ISI subject category ??Microscopy?? (Journal Citation Report) are used to illustrate the proposal.     

The multi-dimensionality of journal impact

In recent studies the issue of the relatedness between journal impact factors and other measures of journal impact have been raised and discussed from both merely empirical and theoretical perspectives. Models of the underlying citation processes suggest distributions with two or more free parameters. Proceeding from the relation between the journals’ mean citation rate and uncitedness and the assumption of an underlying Generalised Waring Distribution (GWD) model, it is found that the journal impact factor alone does not sufficiently describe a journal’s citation impact, while a two-parameter solution appropriately reflects its main characteristics. For the analysis of highly cited publications an additional model derived from the same GWD is suggested. This approach results in robust, comprehensible and interpretable solutions that can readily be applied in evaluative bibliometrics.     

The influence of dispersion on journal impact measures

Scientometrics - A family of measures of a journal’s impact is considered that takes account of the dispersion, as well as the mean, of the number of citations in a journal. These measures,...     

A comparison of Australian university output using journal impact factors

We weighted the output of SCI items from Australian universities using journal impact factors. This provides us with an accessible quality indicator of science journal publishing, and allow us to scale for institutional size in terms of output and research staff. Use of this indicator for the 20 pre-1987 Australian universities demonstrates that although some universities rank highly on output, when scaled for institutional size they are overtaken by some of the smaller, more recently established universities.     

Bias in the journal impact factor

The ISI journal impact factor (JIF) is based on a sample that may represent half the whole-of-life citations to some journals, but a small fraction (<10%) of the citations accruing to other journals. This disproportionate sampling means that the JIF provides a misleading indication of the true impact of journals, biased in favour of journals that have a rapid rather than a prolonged impact. Many journals exhibit a consistent pattern of citation accrual from year to year, so it may be possible to adjust the JIF to provide a more reliable indication of a journal’s impact.     

Journal ranking by selective impact. New method based on SDI results and journal impact factors

Selecting an appropriate set of scientific journals which best meets the users' needs and the dynamics of science requires usage of weight parameters by which journals can be ranked. Previous methods are based on the simple counting of relevant articles, or hits in SDI runs. The new method proposed combines hit numbers in SDI runs and journals' impact factors to a weight parameter called Selective Impact. The experimental results obtained show that ranking by Selective Impact leads to a higher quality of the conclusions to be drawn from journal rank distributions.     

Positive and negative aspects of citation indices and journal impact factors

The Hirsch citation index h is nowadays the most frequently used numerical indicator for the performance of scientists as reflected in their output and in the reaction of the scientific community reflected in citations of individual contributions. A few of the possible improvements of h are briefly reviewed. Garfield??s journal impact factor (IF) characterizes the reaction of the scientific community to publications in journals, reflected in citations of all papers published in any given journal during the preceding 2?years, and normalized against all citable articles during the same period. Again, a few of the possible improvements or supplements of IF are briefly reviewed, including the journal-h index proposed by Braun, Gl?nzel, and Schubert. Ascribing higher weighting factors to citations of individual papers proportionally to IF is considered to be a misuse of useful numerical indices based on citations. At most, one could turn this argument on its head and one can find reasons to ascribe an inverse proportionality relative to IF for individual citations: if a paper is considered worthy to be cited even if it was published in a low-IF journal, that citation ought to be worth more than if the citation would have been from a higher-impact journal. A weight factor reflecting the prestige of the citing author(s) may also be considered.     

Comment on Bornmann (2017): confidence intervals for journal impact factors

Scientometrics - In this Letter to the Editor I comment on a recent Letter from Lutz Bornmann. I argue that the Poisson distribution is not an appropriate simplifying assumption to make when...     

Designing for impact: the effect of rigor and case study design on citations of qualitative case studies in management

Scientometrics - One of the most highly cited papers in management is Eisenhardt’s (Acad Manag Rev 14(4):532–550, 1989) piece on the importance of case study research, in particular...     

The pragmatics of a diachronic journal impact factor

With reference to Vanclay (Scientometrics in press, 2012) the paper argues for a pragmatic approach to the Thomson-Reuter??s journal impact factor. The paper proposes and discusses to replace the current synchronous Thomson-Reuter journal impact factor by an up-to-date diachronic version (DJIF), consisting of a three-year citation window over a one year publication window. The DJIF online data collection and calculation is exemplified and compared to the present synchronous journal impact factor. The paper discusses briefly the dimensions of currency, robustness, understandability and comparability to other impact factors used in research evaluation.     

The effect of additional citations in the stability of Journal Citation Report categories

We use a new approach to study the ranking of journals in JCR categories. The objectives of this study were to empirically evaluate the effect of increases in citations on the computation of the journal impact factor (JIF) for a large set of journals as measured by changes in JIF, and to ascertain the influence of additional citations on the rank order of journals according their new JIFs within JCR groups. To do so, modified JIFs were computed by adding additional citations to the number used by Thomson-Reuters to compute the JIF of journals listed in the JCR for 2008. We considered the effect on rank order of a given journal of adding 1, 2, 3 or more citations to the number used to compute the JIF, keeping everything else equal (i.e., without changing the JIF of other journals in a given group). The effect of additional citations on the internal structure of rankings in JCR groups increased with the number of citations added. In about one third of JCR groups, about half the journals changed their rank order when 1–5 citations were added. However, in general the rank order tended to be relatively stable after small increases in citations.