Dissertations and theses provide a useful starting point for research at all levels of scholarship, from undergraduate students to faculty and professional researchers alike. “Given the vast number of graduate students and Ph.D. candidates who’ve studied a broad range of topics throughout history, there has probably been a dissertation written on almost any topic you can think of,” says April Ellsey, Director of Product Management, Dissertations & Theses, at ProQuest, part of Clarivate.

ProQuest Dissertations & Theses Global is a searchable collection of more than five million dissertations and theses from universities worldwide. More than 3,000 academic libraries around the world subscribe to this database to enhance the research process—and now a breakthrough new feature makes it even easier for users  to find high-quality information about the topic they’re studying.

The features, called Citation Connections, brings more focus and efficiency to the search process by referring researchers to additional (and closely related) sources they might not have discovered on their own or not without hours of cross-referencing reference lists. It does so by using dynamic algorithms to build a network of similar documents based on the overlap in their citation lists. 

“This is one of the biggest innovations we’ve made in the last decade,” Ellsey says. “It expands the scope of relevant information available to students and scholars.”

How the system works

When a dissertation or thesis is chosen from the database, a computational framework compares the references from this “seed” dissertation to millions of reference lists from other topically related documents. Then, it identifies sources that are most frequently cited in that topic, these sources include other dissertations and theses, as well as books, journal articles, newspapers, and bibliographies from anywhere in the world. This citation analysis method is called bibliometric coupling.

As the platform displays the seed dissertation or thesis, there is a panel at the bottom of the Document View page labelled “Similar Dissertations.” Here, users will find additional dissertations and theses with references in common. Those containing the most shared references are displayed first.    

Each result includes a Similarity Index score that indicates the percentage of citations it has in common with the seed document. The closer this score is to 100%, the more likely the two dissertations cover the same topic.

In comparing the bibliographic information found within dissertations and theses to that of other sources, Citation Connections doesn’t just limit this analysis to the ProQuest Dissertations & Theses Global database. The technology also analyzes half a billion citations referenced by sources within the ProQuest platform  which can connect and resolve to sources found in any of the library’s collections beyond the ProQuest platform. 

Any additional source—whether it’s a book, a journal article, or another item—that shares at least five common citations with the seed document is included in a “neighborhood” of related documents. The 20 most frequently cited of these sources appear within a “Foundational Research” panel on the right-hand side of the Document View page. 

This list of further sources is useful when building a foundational understanding of a topic. The assumption behind its creation is that the sources cited most often within a subject area are part of the core knowledge for that topic.

Using a citation network to identify these relationships allows researchers to overcome language and terminology barriers that exist in a traditional keyword search experience.  “This extends the body of research available to users, who aren’t limited by their language proficiency when searching for sources,” Ellsey observes. Another recent enhancement to ProQuest Dissertations & Theses Global also encourages international collaboration. ProQuest has improved the discoverability of non-English dissertations and theses by including titles and abstracts in English alongside the original, further extending the usefulness of Citation Connections and the related sources uncovered.

Making research more efficient

The Citation Connections features were incorporated when ProQuest became part of Clarivate, which has extensive expertise in citation data analysis within its Web of Science portfolio of solutions. 

Although the use of bibliographic comparison exists within other databases, this marks the first time it has been applied to dissertations and theses. ProQuest expects this feature to make research more efficient by enabling users to spend less time searching for sources and more time analyzing information.

“Dissertations and theses offer a wealth of primary knowledge on nearly any topic imaginable. Importantly, this emerging research can be leveraged and built upon by others studying the same topic in countries around the world,” says Angela D’Agostino, vice president of product, dissertations & theses for ProQuest. “Citation Connections make this vast body of knowledge more discoverable, navigable, and relevant to every researcher. With this key advancement in our technology, we envision that dissertations will become an essential starting point for researchers and students at all levels.” 

Alicia Burns, an adjunct professor of education at Wilkes University in Pennsylvania, was one of more than 150 beta testers of the technology. She says the Citation Connections feature has “truly enhanced my searching experience,” noting that the recommendation of similar dissertations “provides us with a sense of validation that our work is meaningful and helps build networks of folks who are interested in similar work.”

One example that demonstrates this connectivity was identified using the selected title “Towards Cell Therapy in Progressive Multiple Sclerosis” from the Hebrew University of Jerusalem, 2019. From this dissertation, we can locate similar dissertations from McGill University (Canada), Bayerische Julius-Maximilians-Universitaet Wuerzburg (Germany), and Harvard University (United States). Foundational Research linked to this selected title included articles from scholarly journals such as The New England Journal of Medicine, Annals of Neurology, Brain (Oxford University Press), and Nature Reviews. By also reviewing the articles’ Cited by counts and dates of publication, you can further determine which articles warrant a deep review, perhaps selecting those articles that have been cited by over 1,000 other papers. 

Librarians can learn more at https://about.proquest.com/en/products-services/pqdtglobal/

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