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April 13, 2009
Issue No. 80

Table of Contents

Links to Thomson Scientific Impact Factors Now in LaneConnex

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by Marilyn Tinsley

One measure of the importance or impact of various journals is the Thomson Scientific Impact Factor, developed by Eugene Garfield, founder of the Institute for Information Science. Thomson Scientific began to publish impact factors in Journal Citation Reports® (JCR®) in 1975. The Impact Factor is calculated for science and social science journals, based on the average number of times articles in each journal are cited within a two-year period. This number has some limitations, and should be viewed as part of a trend over several years, and/or in the context of a subject area. Also, note that it applies only to the journals indexed by Science Citation Index® and Social Science Citation Index®.

Looking at a journal in the context of an entire field will determine whether an impact factor is high or low. For example, the highest impact factor in psychiatry is 15.976, for Archives of General Psychiatry. Web of Science indexes 94 titles in this field, and the lowest impact factor is 0.061. In oceanography, the highest impact factor is 3.615, for Oceanography and Marine Biology, and the lowest impact factor is 0.070, so the range for the fifty titles included in this category is quite small. The significance of impact factors is such that two journals with an impact factor of 3 could be highly rated (oceanography) or in the bottom half of a group (psychiatry).

LaneConnex and the Lane Catalog now include links to the Thomson Scientific Impact Factor Trend Graphs for approximately 3900 titles. By searching for a journal title in Lane's catalog or LaneConnex, or by finding the title on Lane's eJournals page, you can follow the Impact Factor link to the Trend Graph. This shows the current Impact Factor, the trend over the last 5 years, and the calculations. The example below shows an entry on Lane's eJournals page and the linked impact factor trend graph.

Impact Factor Graph for American Journal of Cardiology
Impact Factor Graph for American Journal of Cardiology

American Journal of Cardiology

To view the title within its field, click on the Return to Journal button. Next, click on View Journal Summary List to see all the journals in the category with their respective article and citation data. Additional measures available are: the Immediacy index, Cited Half-life, Eigenfactor Score, and Article Influence Score. All these metrics can provide information about the importance or impact of a particular journal.

To find impact factors for journals not listed on LaneConnex, go to the Journal Citation Reports (JCR) database on Lane's databases list or on the SULAIR Databases and Articles page.

For further information about Impact Factors and their uses, visit the Web of Science site.