What does the Web of Science five-year synchronous impact factor have to offer?

• 来源期刊: 中国文献情报（英文刊）
• 关键词: Synchronous impact factor Wilcoxon matched-pairs Signed-ranks test
• 年，卷（期）: 2009,（3）
• 页码范围: 1-7
• 页数: 7页
• 语种: 英文

摘要

With a random sample of 10 JCR (Science) subject areas it is shown that the 2-year and the 5-year impact factor of journals lead statistically to the same ranking per category.Yet in a majority of cases,the 5-year impact factor is larger than the 2-year one.