Leiden Ranking The CWTS Leiden Ranking 2015 is based on publications in Thomson Reuters’ Web of Science database (Science Citation Index Expanded, Social Sciences Citation Index, and Arts & Humanities Citation Index) in the period 2010– 2013. http: //www. leidenranking. com/methodology/datacollection 13
If I have seen further it is by standing on the shoulders of giants. Newton, I. 20
Impact Factor (IF) The journal Impact Factor is the average number of times articles from the journal published in the past two years have been cited in the JCR year. The Impact Factor is calculated by dividing the number of citations in the JCR year by the total number of articles published in the two previous years. An Impact Factor of 1. 0 means that, on average, the articles published one or two year ago have been cited one time. An Impact Factor of 2. 5 means that, on average, the articles published one or two year ago have been cited two and a half times. Citing articles may be from the same journal; most citing articles are from different journals. 23
The impact factor (IF) of an academic journal is a measure reflecting the average number of citations to recent articles published in the journal. It is frequently used as a proxy for the relative importance of a journal within its field, with journals with higher impact factors deemed to be more important than those with lower ones. The impact factor was devised by Eugene Garfield, the founder of the Institute for Scientific Information. Impact factors are calculated yearly starting from 1975 for those journals that are indexed in the Journal Citation Reports. (Wikipedia) 24
インパクトファクターは研究業績評価に使えない Impact factors are widely used to rank and evaluate journals. They also often used inappropriately as surrogates in evaluation exercises. The inventor of the Science Citation Index warns against the indiscriminate use of these data. Eugene Garfield. How can impact factors be improved? British Medical Journal. Vol. 313, 1996. p. 411 -413. インパクトファクターは「学術雑誌」の指標であり、研究業績 評価指標ではない。 インパクトファクターの開発者 ガーフィールド 36