Evidence of open access of scientific publications in Google Scholar: A large-scale analysis. Issue 3 (August 2018)

• Record Type: Journal Article
• Authors: Martín-Martín, Alberto; Costas, Rodrigo; van Leeuwen, Thed; Delgado López-Cózar, Emilio
• Is Part Of: Journal of informetrics. Volume 12:Issue 3(2018)
• Page Start: 819
• Page End: 841
• Publication Date: 2018-08
• Subjects: Academic publishers -- Academic search engines -- Academic social networks -- Creative commons -- CrossRef -- Google Scholar -- Institutional repositories -- Open access -- Open research metadata -- ResearchGate -- Self-Archiving; Library statistics -- Periodicals; Information science -- Statistical methods -- Periodicals; Bibliometrics -- Periodicals; Bibliothèques -- Statistiques -- Périodiques; Sciences de l'information -- Méthodes statistiques -- Périodiques; Bibliométrie -- Périodiques; 020.727
• DOI: 10.1016/j.joi.2018.06.012
• Languages: English
• ISSNs: 1751-1577

Abstract

Highlights: 55% of the documents covered by Web of Science from 2009 and 2014 are freely available in some form from Google Scholar. 23% of documents are available from the publisher, 17% from repositories, and 40% from other sources, mainly ResearchGate. Many publishers still do not declare a clear user license in CrossRef, difficulting the identification of OA types. OA levels are higher in the Natural and Health sciences, and lower in Social Sciences, Engineering, and Arts & Humanities. OA levels are higher for publications produced in Europe, USA, and Brazil (36–50%), than in Asian countries (18–36%). Abstract: This article uses Google Scholar (GS) as a source of data to analyse Open Access (OA) levels across all countries and fields of research. All articles and reviews with a DOI and published in 2009 or 2014 and covered by the three main citation indexes in the Web of Science (2, 269, 022 documents) were selected for study. The links to freely available versions of these documents displayed in GS were collected. To differentiate between more reliable (sustainable and legal) forms of access and less reliable ones, the data extracted from GS was combined with information available in DOAJ, CrossRef, OpenDOAR, and ROAR. This allowed us to distinguish the percentage of documents in our sample that are made OA by the publisher (23.1%, including Gold, Hybrid, Delayed, and Bronze OA) from those available as Green OA (17.6%), and those available from other sources (40.6%, mainly due to ResearchGate). The data shows an overall free availability of 54.6%, with important differences at the country and subject category levels. The data extracted from GS yielded very similar results to those found by other studies that analysed similar samples of documents, but employed different methods to find evidence of OA, thus suggesting a relative consistency among methods.