The book draws on academic and scientific sources as well as 'gray literature
,' which includes sources produced by government agencies, nonprofits, think tanks, and special interest groups, as well as sources from journalism and media.
Variation in outcomes across studies, heterogeneity among studies, potential selection bias by excluding gray literature
, and the inability to establish causal links from findings because of the cross-sectional nature of the studies analyzed were potential limitations in the study, they reported.
Even though evidence-based studies are lacking, there is an ocean of "gray literature
," often nonpeer-reviewed case studies and project-based reports written by practitioners in the field or by organizations such as the United Nations Children's Fund.
On the other end of the spectrum, for S2, the three researchers searched gray literature
studies through Google Scholar, considering the small number of publications on the topic yielded from the electronic search.
Rapid extreme event attribution and communication of results through gray literature
provide useful information for stakeholders and the public but warrant further community discussion regarding how to mitigate potential risks.
The first source for gray literature
was Google Scholar.
They found that meta-analyses that included "gray literature
" (i.e., unpublished studies) in the corpus of studies analyzed were almost 3 times less likely to find publication bias in the results compared to meta-analyses that excluded gray literature
Our findings show that a librarian can greatly facilitate the reporting practices for some of the methodological elements, such as the flow diagram of the study inclusion process, the date that the search was updated, the full search strategy, the use of subject-specific and regional bibliographic databases for data collection, and searches of the gray literature
. Most of the remaining methodological elements in our instrument were reported consistently, regardless of the presence of librarian involvement (e.g., language restrictions selection criteria, gathering unpublished data/ information).
They even searched Google for what is known as "gray literature
," material not published in recognized scientific journals.
But there is another level of publishing that we can tackle right away with less upfront investment: bringing order to the world of gray literature
In comparison with other citation tracking tools such as Web of Science and Scopus, Google Scholar's citation counts are generally larger, because they cover gray literature
as well as established academic publications.