Science through Wikipedia: A novel representation of open knowledge through co-citation networks

With more than 170 editions, the English language version accounted for 5.5 million entries in January 2018 (approximately 11.7% of the entire encyclopedia). Given that worldwide Wikipedia is a top ten website in terms of traffic-according to Alexa (https://www.alexa.com/topsites , consulted on July 24, 2019)-and is one of the preferred results provided by search engines, it has become an outstanding tool for the dissemination of knowledge within a model based on openness and collaboration. Perhaps Wikipedia’s most important achievement has been to challenge traditional epistemologies based on authorship and authority and move towards a more social, distributed epistemology [3]. Wikipedia is therefore the result of a negotiation process that provides us with a representation of knowledge in society, offering tremendous research opportunities. For instance, some authors have studied the discursive constructions of concepts such as globalization [4] or historical landmarks like the 9/11 attacks [5]. The Preprint paper published in PLOS ONE: https://doi.org/10.1371/journal.pone.0228713 Preprint paper published in PLOS ONE: https://doi.org/10.1371/journal.pone . 0228713 3 process of negotiation behind an article is often driven by the principles of verifiability and reliability in relation to the sources supporting the statements made. Specialized publications are among the preferred sources of reference (https://en.wikipedia.org/wiki/Wikipedia:Identifying_reliable_sources , consulted on July 24, 2019), mainly in the form of scholarly material and prioritizing academic and peer-reviewed publications, as well as scholarly monographs and textbooks.

Consequently, the social construction of knowledge on Wikipedia is explicitly and intentionally connected to scholarly research published under the peer-review model. This has offered us the opportunity to investigate how Science and Wikipedia interrelate. Although Wikipedia is not a primary source of information, some studies have examined citations of Wikipedia articles [6,7]. Moreover, numerous studies have analyzed how Wikipedia articles cite scholarly publications because contributors are strongly recommended to do so by the encyclopedia itself. Studies have focused on the analysis of reference and citation patterns in specific areas of knowledge [8], on exploring Wikipedia’s value as a source when evaluating scientific activity [9], or on Wikipedia’s role as a platform that promotes open access research [10].

Furthermore, some studies undertaken within the last decade could be said to be framed within the Altmetric perspective because they have used indicators extracted from the social media to measure dimensions of academic impact [11,12,13]. Wikipedia references to scientific articles can provide highly valuable altmetric information given that the inclusion of references is not a trivial activity and is usually subject to community scrutiny. For instance, the Altmetric Attention Score-an indicator created by Altmetric.com-gives this type of citation a high value (3) that is higher than mentions on Facebook (0.25) or Twitter (1), but lower than references to blogs (5) and news feeds (8).

Networks have also been used for knowledge representation in order to visualize differences between the Universal Decimal Classification category structure and that generated by Wikipedia itself [14], to generate automated taxonomies and visualizations of scientific fields [15], and to show connections between articles [16]; furthermore, studies based on the complex networks approach have also been reported [17].

One way to address knowledge representation from a bibliometric perspective is through the use of cocitations [18], an approach that uses references in common received from a third document as a proxy for similarity between two scientific documents. Co-citations have been used to observe similarities between words [19] or areas of knowledge [20].

From an Altmetric perspective, the concept of co-citation was transferred to the online world giving rise to co-link analysis [21], where documents are replaced by webpages or websites, and citations are replaced by links. Co-link analysis has successfully mapped scientific knowledge [22] and analyzed fields such as universities [23], politics [24] or business [25].

These different concepts where recently combined and applied to Wikipedia by Torres-Salinas, Romero-Frías and Arroyo-Machado [26] and tested in the field of the Humanities by mapping specialties and journals. The present study uses Wikipedia to draw a social representation of scientific knowledge and the areas into which it is divided. After collecting