“Citation impact”, the total number of citations per article, has a variety of different applications. For instance, when examining the works of 3 Nobel prize winners, Drs. Esaki, Tonegawa and Fukui, using SciSearch on STN, citation impact comes out high with figures of 28.03, 53.57 and 16.13, respectively. These high figures reflect the unique features of the three fields of Physics, Medicine and Chemistry. It is also interesting to find that “zero impact” rates (articles with no citations) are close to 20% for each scientist, with figures of 30, 40 and 31 articles, respectively. Although the total number of items from Japan equal about one million, citation impact for Japanese articles is 1.26 and the zero impact rate is 53%. Limiting these further by language to Japanese, citation impact is reduced to 0.22 and the zero impact rate rises to 83%. In general, key articles from Japanese authors are published in overseas core journals in English, although 128 journals from Japan have been included in SciSearch in 1996, among which 33 are in the Japanese language. The remaining Japanese journals are out of the scope & coverage of SciSearch, mainly because those are in Japanese. As such, citation impact may appear to be lower than it actually is, and the zero impact rate may appear to be unusually high for Japan. Furthermore, citation impact should not be mistaken for impact factor. Impact factor is the evaluation of the entire journal by citation, whereas citation impact is the evaluation of the author and his articles.
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