A new methodology for comparing Google Scholar and Scopus

作者：

Highlights：

• A new methodology is proposed for comparing Google Scholar (GS) with Scopus, focusing on indexing speed and duplicate citation counts.

• The ratio of GS over Scopus citation varies across subject fields between 1.0 and 4.0, and is for Open Access journals higher than for other journals.

• The linear correlation between GS and Scopus citation counts at the article level is high: Pearson’s R is in the range of 0.8–0.9.

• A median Scopus indexing delay of two months compared to GS is largely due to missing cited references in articles in press in Scopus.

• Double citation counts in GS due to multiple versions of the same document occurs in less than 2% of cases.

摘要

•A new methodology is proposed for comparing Google Scholar (GS) with Scopus, focusing on indexing speed and duplicate citation counts.•The ratio of GS over Scopus citation varies across subject fields between 1.0 and 4.0, and is for Open Access journals higher than for other journals.•The linear correlation between GS and Scopus citation counts at the article level is high: Pearson’s R is in the range of 0.8–0.9.•A median Scopus indexing delay of two months compared to GS is largely due to missing cited references in articles in press in Scopus.•Double citation counts in GS due to multiple versions of the same document occurs in less than 2% of cases.

论文关键词：Google Scholar,Scopus,Source coverage,Indexing delay,Citation counts,Open Access journals,Duplicate citations,Document versions

论文评审过程：Received 16 December 2015, Revised 26 April 2016, Accepted 26 April 2016, Available online 30 April 2016, Version of Record 30 April 2016.

论文官网地址：https://doi.org/10.1016/j.joi.2016.04.017