Welcome to Journal Citation Reports®, a unique Web-based research tool that allows you to evaluate and compare journals using citation data drawn from approximately 10,000 scholarly and technical journals and conference proceedings from more than 3,300 publishers in over 60 countries. Journal Citation Reports is the only source of citation data on journals, and includes virtually all specialties in the areas of science, technology, and social sciences.
Each year, Thomson Reuters receives feedback from publishers after publication of the annual Journal Citation Reports in June. This feedback is carefully and systematically reviewed. As a result, selected JCR data may be modified and adjustments made to metrics such as the Journal Impact Factor. A re-evaluation of 2008 JCR data has been completed, and changes have been made to 55 journals. To see a full list of affected titles, please follow the link below:
This release of Journal Citation Reports provides 2008 data. The 2009 edition of Journal Citation Reports will be made available summer 2010.
Conference Proceedings Citations in JCR
The 2008 Journal Citation Reports includes citation data from all conference proceedings regardless of publication type. With this release, proceedings published in books, book series, and journals all contribute citation data. In prior years, citations from proceedings published in books were not counted. However, proceedings published in journals and book series have always been counted.
Overall, the additional material accounts for an increase in total citations of approximately 2% (1.1 million citations added to a total of 47 million).
As a result, JCR Impact Factors for journals in certain fields, such as computer engineering, may see larger increases than expected because important research is often published as proceedings in these fields.
The addition of more citations from conference proceedings does not represent a change in policy or scope. JCR has always counted citations from conference proceedings. The only difference is that now conference proceedings published in books contribute citation data to JCR.
Regional Content Expansion
In the past three years, more than 1,500 journals that focus on topics of regional interest have been added to Web of Science. Data used to calculate JCR metrics include citations from these journals. In addition, several of these titles are included in the list of new titles available in the 2008 JCR. To get information about the new regional content in JCR, go to http://isiwebofknowledge.com/products_tools/multidisciplinary/webofscience/contentexp/.
To access the list of new titles, go to http://isiwebofknowledge.com/products_tools/analytical/jcr/08jcr-newtitles/.
Due to the significant effect of self citations on their Impact Factors, metrics for a number of titles were not published in the 2008 JCR. Suppressed titles were found to have exceptionally high self citation rate, some over 90% This level of self citation has a profound effect on the rank of the journal in its category and does not reflect accurately the journal’s true participation, by way of citation, in the scholarly literature of its subject. The meaning of Impact Factor as an objective and integral measure of a journal’s participation in the scholarly literature on a particular subject becomes questionable at this level of self citation. It is for this reason that the following journals do not appear in the 2008 JCR. JCR Staff will monitor these journals going forward and the titles will be re-listed in a future edition of JCR when the problem of excessive self citations has been resolved. In the meantime, coverage of these journals in Web of Science and other Thomson Reuters products is not changed.
When citing Journal Citation Reports, be sure to include the following information:
Impact Factor Box Plot
The algorithm on which the category box plot is based is incorrectly represented in Help. Here is a corrected explanation:
The Impact Factor box plot depicts the distribution of Impact Factors for all journals in the category. The horizontal line that forms the top of the box is the 75th percentile (Q3). The horizontal line that forms the bottom is the 25th percentile (Q1). The horizontal line that intersects the box is the median Impact Factor for the category. The cross represents the mean value.
Horizontal lines above and below the box, called whiskers, represent maximum and minimum values.
The top whisker is the smaller of the following two values:
The bottom whisker is the larger of the following two values:
An open circle represents an outlier, which is a value greater than the value represented by the top whisker. An asterisk represents a "far" outlier, which is a value greater than the sum of the value represented by the top whisker and 5(Q3 IF - Q1 IF).
The explanations of Eigenfactor Score and Article Influence provided in Help have been revised here for improved clarity and accuracy.
The Eigenfactor Score calculation is based on the number of times articles from the journal published in the past five years have been cited in the JCR year, but it also considers which journals have contributed these citations so that highly cited journals will influence the network more than lesser cited journals. References from one article in a journal to another article from the same journal are removed, so that Eigenfactor Scores are not influenced by journal self-citation.
Article Influence Score
The Article Influence determines the average influence of a journal's articles over the first five years after publication. It is calculated by dividing a journal’s Eigenfactor Score by the number of articles in the journal, normalized as a fraction of all articles in all publications. This measure is roughly analogous to the 5-Year Journal Impact Factor in that it is a ratio of a journal’s citation influence to the size of the journal’s article contribution over a period of five years.
The mean Article Influence Score is 1.00. A score greater than 1.00 indicates that each article in the journal has above-average influence. A score less than 1.00 indicates that each article in the journal has below-average influence.
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This file was last updated on 09/30/2009
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