摘要 :
We have compared the 2-year and 5-year impact factors (IFs), normalized impact factors (NIFs) and rank normalized impact factors (RNIFs) of open access (OA) and subscription journals across the 22 major fields delineated in Essent...
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We have compared the 2-year and 5-year impact factors (IFs), normalized impact factors (NIFs) and rank normalized impact factors (RNIFs) of open access (OA) and subscription journals across the 22 major fields delineated in Essential Science Indicators. Journal Citation Reports (JCR) 2012 has assigned 2-year IF to 1,073 OA and 7,290 subscription journals and 5-year IF to 811 OA and 6,705 subscription journals. Overall 12.8% of journals listed in JCR are OA, but a higher percentage of journals are OA in 9 fields, including multidisciplinary (31%), agriculture (19.1%) and microbiology (19.1). Overall 2-year IF is higher than 5-year IF in about 31.5% journals in both OA and subscription journals. But among physics journals, two-thirds of OA journals and 58% of subscription journals have a higher 2-year IF. For multidisciplinary journals the mean RNIF is higher for OA journals than subscription journals. Higher proportion of subscription journals had mean RNIF above 0.5: 361 of 1,073 OA journals (33.6%) and 3,857 of 7,280 subscription journals (52.9%) had a 2-year mean RNIF above 0.5 and 277 of 811 OA journals (34.2%) and 3,453 of 6705 (51.5%) subscription journals had a 5-year mean RINF above 0.5. Moving to OA has proven to be advantageous to developing country journals; it has helped a large number of Latin American and many Indian journals improve their IF.
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摘要 :
We have compared the 2-year and 5-year impact factors (IFs), normalized impact factors (NIFs) and rank normalized impact factors (RNIFs) of open access (OA) and subscription journals across the 22 major fields delineated in Essent...
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We have compared the 2-year and 5-year impact factors (IFs), normalized impact factors (NIFs) and rank normalized impact factors (RNIFs) of open access (OA) and subscription journals across the 22 major fields delineated in Essential Science Indicators. Journal Citation Reports (JCR) 2012 has assigned 2-year IF to 1,073 OA and 7,290 subscription journals and 5-year IF to 811 OA and 6,705 subscription journals. Overall 12.8% of journals listed in JCR are OA, but a higher percentage of journals are OA in 9 fields, including multidisciplinary (31%), agriculture (19.1%) and microbiology (19.1). Overall 2-year IF is higher than 5-year IF in about 31.5% journals in both OA and subscription journals. But among physics journals, two-thirds of OA journals and 58% of subscription journals have a higher 2-year IF. For multidisciplinary journals the mean RNIF is higher for OA journals than subscription journals. Higher proportion of subscription journals had mean RNIF above 0.5: 361 of 1,073 OA journals (33.6%) and 3,857 of 7,280 subscription journals (52.9%) had a 2-year mean RNIF above 0.5 and 277 of 811 OA journals (34.2%) and 3,453 of 6705 (51.5%) subscription journals had a 5-year mean RINF above 0.5. Moving to OA has proven to be advantageous to developing country journals; it has helped a large number of Latin American and many Indian journals improve their IF.
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摘要 :
We have compared the 2-year and 5-year impact factors (IFs), normalized impact factors (NIFs) and rank normalized impact factors (RNIFs) of open access (OA) and subscription journals across the 22 major fields delineated in Essent...
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We have compared the 2-year and 5-year impact factors (IFs), normalized impact factors (NIFs) and rank normalized impact factors (RNIFs) of open access (OA) and subscription journals across the 22 major fields delineated in Essential Science Indicators. Journal Citation Reports (JCR) 2012 has assigned 2-year IF to 1,073 OA and 7,290 subscription journals and 5-year IF to 811 OA and 6,705 subscription journals. Overall 12.8% of journals listed in JCR are OA, but a higher percentage of journals are OA in 9 fields, including multidisciplinary (31%), agriculture (19.1%) and microbiology (19.1). Overall 2-year IF is higher than 5-year IF in about 31.5% journals in both OA and subscription journals. But among physics journals, two-thirds of OA journals and 58% of subscription journals have a higher 2-year IF. For multidisciplinary journals the mean RNIF is higher for OA journals than subscription journals. Higher proportion of subscription journals had mean RNIF above 0.5: 361 of 1,073 OA journals (33.6%) and 3,857 of 7,280 subscription journals (52.9%) had a 2-year mean RNIF above 0.5 and 277 of 811 OA journals (34.2%) and 3,453 of 6705 (51.5%) subscription journals had a 5-year mean RINF above 0.5. Moving to OA has proven to be advantageous to developing country journals; it has helped a large number of Latin American and many Indian journals improve their IF.
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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...
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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, reflecting 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.
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For comparisons of citation impacts across fields and over time, bibliometricians normalize the observed citation counts with reference to an expected citation value. Percentile-based approaches have been proposed as a non-paramet...
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For comparisons of citation impacts across fields and over time, bibliometricians normalize the observed citation counts with reference to an expected citation value. Percentile-based approaches have been proposed as a non-parametric alternative to parametric central-tendency statistics. Percentiles are based on an ordered set of citation counts in a reference set, whereby the fraction of papers at or below the citation counts of a focal paper is used as an indicator for its relative citation impact in the set. In this study, we pursue two related objectives: (1) although different percentile-based approaches have been developed, an approach is hitherto missing that satisfies a number of criteria such as scaling of the per-centile ranks from zero (all other papers perform better) to 100 (all other papers perform worse), and solving the problem with tied citation ranks unambiguously. We introduce a new citation-rank approach having these properties, namely P100; (2) we compare the reliability of P100 empirically with other percentile-based approaches, such as the approaches developed by the SClmago group, the Centre for Science and Technology Studies (CWTS), and Thomson Reuters (Incites), using all papers published in 1980 in Thomson Reuters Web of Science (WoS). How accurately can the different approaches predict the long-term citation impact in 2010 (in year 31) using citation impact measured in previous time windows (years 1-30)? The comparison of the approaches shows that the method used by Incites overestimates citation impact (because of using the highest percentile rank when papers are assigned to more than a single subject category) whereas the SClmago indicator shows higher power in predicting the long-term citation impact on the basis of citation rates in early years. Since the results show a disadvantage in this predictive ability for P100 against the other approaches, there is still room for further improvements.
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Prestigious journals are widely admired for publishing quality scholarship, yet the primary indicators of journal prestige (i.e., impact factors) do not directly assess audience admiration. Moreover, the publication landscape has ...
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Prestigious journals are widely admired for publishing quality scholarship, yet the primary indicators of journal prestige (i.e., impact factors) do not directly assess audience admiration. Moreover, the publication landscape has changed substantially in the last 20 years, with electronic publishing changing the way we consume scientific research. Given that it has been 18 years since the publication of the last journal prestige survey of SIOP members, the authors conducted a new survey and used these results to reflect on changing practices within industrial and organizational (I-O) psychology. SIOP members (n = 557) rated the prestige and relevance of I-O and management journals. Responses were analyzed according to job setting, and were compared to a survey conducted by Zickar and Highhouse (2001) in 2000. There was considerable consistency in prestige ratings across settings (i.e., management department vs. psychology department; academic vs. applied), especially among the top journals. There was considerable variance, however, in the perceived usefulness of different journals. Results also suggested considerable consistency across the two time periods, but with some increases in prestige among OB-oriented journals. Changes in the journal landscape are discussed, including the rise of OHP as a topic of concentration in I-O. We suggest that I-O programs will continue to attract the top researchers in talent management and OHP, which should result in the use of a broader set of journals for judging I-O program impact.
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The growing importance of academic journals' Impact Factor (IF) is reshaping the research arena. In this paper we discuss the possible impact of the IF on tourism research and on key players such as editors of top-tier tourism jou...
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The growing importance of academic journals' Impact Factor (IF) is reshaping the research arena. In this paper we discuss the possible impact of the IF on tourism research and on key players such as editors of top-tier tourism journals, students, researchers as well as directors of tourism academic units. It also examines the impact on the public whose funds make up part of scholars' salaries and, to some extent, research grants. It is argued here that by encouraging researchers to target only journals with a high IF, research may come to a standstill, as exploratory, industry-related or critical studies may cease being conducted and published. This is a call to minimize the reliance on the IF and its glorification as an indicator of research quality and researchers' performance. (C) 2015 Elsevier Ltd. All rights reserved.
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Percentiles have been established in bibliometrics as an important alternative to mean-based indicators for obtaining a normalized citation impact of publications. Percentiles have a number of advantages over standard bibliometric...
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Percentiles have been established in bibliometrics as an important alternative to mean-based indicators for obtaining a normalized citation impact of publications. Percentiles have a number of advantages over standard bibliometric indicators used frequently: for example, their calculation is not based on the arithmetic mean which should not be used for skewed bibliometric data. This study describes the opportunities and limits and the advantages and disadvantages of using percentiles in bibliometrics. We also address problems in the calculation of percentiles and percentile rank classes for which there is not (yet) a satisfactory solution. It will be hard to compare the results of different percentile-based studies with each other unless it is clear that the studies were done with the same choices for percentile calculation and rank assignment.
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When excess returns are used to estimate linear stochastic discount factor (SDF) models, researchers often adopt a normalization of the SDF that sets its mean to 1, or one that sets its intercept to 1. These normalizations are oft...
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When excess returns are used to estimate linear stochastic discount factor (SDF) models, researchers often adopt a normalization of the SDF that sets its mean to 1, or one that sets its intercept to 1. These normalizations are often treated as equivalent, but they are subtly different both in population, and in finite samples. Standard asymptotic inference relies on rank conditions that differ across the two normalizations, and which can fail to differing degrees. I first establish that failure of the rank conditions is a genuine concern for many well-known SDF models in the literature. I also describe how failure of the rank conditions can affect inference, both in population and in finite samples. I propose using tests of the rank conditions not only as a diagnostic device, but also for model reduction. I show that this model reduction procedure has desirable properties in a Monte-Carlo experiment with a calibrated model.
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Using percentile shares, one can visualize and analyze the skewness in bibliometric data across disciplines and over time. The resulting figures can be intuitively interpreted and are more suitable for detailed analysis of the eff...
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Using percentile shares, one can visualize and analyze the skewness in bibliometric data across disciplines and over time. The resulting figures can be intuitively interpreted and are more suitable for detailed analysis of the effects of independent and control variables on distributions than regression analysis. We show this by using percentile shares to analyze so-called "factors influencing citation impact" (FICs; e.g., the impact factor of the publishing journal) across years and disciplines. All articles (n=2,961,789) covered by WoS in 1990 (n=637,301), 2000 (n =919,485), and 2010 (n =1,405,003) are used. In 2010, nearly half of the citation impact is accounted for by the 10% most-frequently cited papers; the skewness is largest in the humanities (68.5% in the top-10% layer) and lowest in agricultural sciences (40.6%). The comparison of the effects of the different FICs (the number of cited references, number of authors, number of pages, and JIF) on citation impact shows that the JIF has indeed the strongest correlations with the citation scores. However, the correlation between FICs and citation impact is lower, if citations are normalized instead of using raw citation counts. (C) 2016 Elsevier Ltd. All rights reserved.
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