Scopus's Source Normalized Impact per Paper (SNIP) Versus a Journal Impact Factor Based on Fractional Counting of Citations
Scopus's Source Normalized Impact per Paper (SNIP) Versus a Journal Impact Factor Based on Fractional Counting of Citations
复制标题
DOI：
10.1002/asi.21371
复制
发表时间：
2010-11-01
影响因子：
--
通讯作者：
Opthof, Tobias
中科院分区：
文献类型：
--
作者：
Leydesdorff, Loet;Opthof, Tobias
影响因子（以及类似的指标，如Scimago期刊排名）存在两个问题：（a）引用行为在科学领域之间存在差异，因此导致系统性差异，（B）没有统计数据告诉我们差异是否显著。Scopus最近推出的“每篇论文的源标准化影响”指标试图解决这两个问题中的第一个，但涉及到一些标准化决策，这使得它不可能测试的显着性。使用基于影响与引用文件中的参考文献数量成比例的假设的引用分数计数，可以在论文水平上对引用进行上下文化，并且可以测试集合的聚合影响的显著性。可以看出，《数学年鉴》的加权影响（0.247）并不比《分子细胞》（0.386）低多少，尽管它们的影响因子（分别为2.793和13.156）相差五倍。
Impact factors (and similar measures such as the Scimago Journal Rankings) suffer from two problems: (a) citation behavior varies among fields of science and, therefore, leads to systematic differences, and (b) there are no statistics to inform us whether differences are significant. The recently introduced "source normalized impact per paper" indicator of Scopus tries to remedy the first of these two problems, but a number of normalization decisions are involved, which makes it impossible to test for significance. Using fractional counting of citations based on the assumption that impact is proportionate to the number of references in the citing documents citations can be contextualized at the paper level and aggregated impacts of sets can be tested for their significance. It can be shown that the weighted impact of Annals of Mathematics (0.247) is not so much lower than that of Molecular Cell (0.386) despite a five-fold difference between their impact factors (2.793 and 13.156, respectively).