The Role of Google Scholar in Evidence Reviews and Its Applicability to Grey Literature Searching.
The Role of Google Scholar in Evidence Reviews and Its Applicability to Grey Literature Searching.
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DOI：
10.1371/journal.pone.0138237
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发表时间：
2015
期刊：
影响因子：
3.7
通讯作者：
Kirk S
中科院分区：
文献类型：
--
作者：
Haddaway NR;Collins AM;Coughlin D;Kirk S
Google Scholar（GS）是一个常用的基于网络的学术搜索引擎，收录了200万至1亿条学术和灰色文献（非商业学术出版商正式出版的文章）的记录。Google Scholar整理来自互联网的结果，并免费使用。因此，作为一种文献检索方法，特别是系统评价所要求的灰色文献检索方法，它受到了相当大的关注。GS作为一个独立的资源的依赖一直存在很大的争议，但是，其在灰色文献检索的有效性尚未得到调查。利用环境科学的系统评价案例研究，我们调查了GS在系统评价和灰色文献搜索中的效用。我们的研究结果表明，GS结果包含中等数量的灰色文献，大多数平均在第80页。我们还发现，当专门搜索时，使用Web of Science识别的大多数文献也使用GS找到。然而，我们的研究结果显示，当在Web of Science和GS中使用相似的搜索字符串时，结果的重叠程度为中等/较差（10-67%），并且GS在六个案例研究中的五个中遗漏了一些重要文献。此外，一般的GS搜索没有发现任何灰色文献的案例研究，涉及手动搜索组织的网站。如果用于灰色文献的系统评价，我们建议检索文章标题，重点是前200到300个结果。我们的结论是，虽然Google Scholar可以找到很多灰色文献和特定的已知研究，但不应单独用于系统综述检索。相反，它是对其他传统搜索方法的有力补充。此外，我们提倡使用工具来透明地记录和编目GS搜索结果，以保持高水平的透明度和更新能力，这对系统性审评至关重要。
Google Scholar (GS), a commonly used web-based academic search engine, catalogues between 2 and 100 million records of both academic and grey literature (articles not formally published by commercial academic publishers). Google Scholar collates results from across the internet and is free to use. As a result it has received considerable attention as a method for searching for literature, particularly in searches for grey literature, as required by systematic reviews. The reliance on GS as a standalone resource has been greatly debated, however, and its efficacy in grey literature searching has not yet been investigated. Using systematic review case studies from environmental science, we investigated the utility of GS in systematic reviews and in searches for grey literature. Our findings show that GS results contain moderate amounts of grey literature, with the majority found on average at page 80. We also found that, when searched for specifically, the majority of literature identified using Web of Science was also found using GS. However, our findings showed moderate/poor overlap in results when similar search strings were used in Web of Science and GS (10–67%), and that GS missed some important literature in five of six case studies. Furthermore, a general GS search failed to find any grey literature from a case study that involved manual searching of organisations’ websites. If used in systematic reviews for grey literature, we recommend that searches of article titles focus on the first 200 to 300 results. We conclude that whilst Google Scholar can find much grey literature and specific, known studies, it should not be used alone for systematic review searches. Rather, it forms a powerful addition to other traditional search methods. In addition, we advocate the use of tools to transparently document and catalogue GS search results to maintain high levels of transparency and the ability to be updated, critical to systematic reviews.