Scholarly Knowledge Graphs (SKGs)

SKG stands for Scholarly Knowledge Graph. It is a structured academic data system that connects different research-related entities such as papers, authors, institutions, citations, and journals.

In simple words, an SKG helps us understand who published what, where it was published, and how that work is connected through citations and research relationships.

What is an SKG?

A Scholarly Knowledge Graph is more than just a list of research papers. It organizes academic information in a connected way. Instead of storing only titles and authors, it also links papers to authors, authors to institutions, papers to journals, and papers to other papers through citations.

Because of these connections, SKGs are useful for searching, analysis, discovery, and visualization of scholarly information.

Main Elements of an SKG

Papers

These are research articles, conference papers, reviews, books, chapters, datasets, and other scholarly records.

Authors

These represent the researchers who wrote the scholarly works and their collaboration networks.

Institutions

These show the universities, colleges, research labs, or organizations connected with authors.

Citations

Citations show how one paper refers to another paper. This helps measure influence and scholarly impact.

Journals

These are the publication sources where scholarly works appear, such as journals, conferences, or repositories.

Relationships

The most important feature of an SKG is the connection between all these entities in a structured graph form.

Why are SKGs useful?

Searching

They help users find papers, authors, institutions, journals, and topics more effectively.

Analysis

They support citation analysis, author productivity analysis, institutional output analysis, and subject trends.

Visualization

They allow the creation of citation networks, co-author networks, and collaboration maps.

Research Evaluation

They are helpful for understanding research impact, visibility, and scholarly communication patterns.

Important Terms in Simple Words

Open

An open platform makes its data or services publicly accessible, often with fewer restrictions.

Closed

A closed platform restricts access and usually requires a subscription, license, or institutional membership.

Free

A free platform can be used without payment, although some limits may still apply.

Paid

A paid platform requires subscription or purchase for access to its content and features.

Freemium

A freemium platform gives some basic access free of cost, but advanced features are paid.

Curated

Curated means the data is selected, checked, and organized with quality control standards.

Major SKG Platforms

The following table gives a simple comparison of major scholarly knowledge graph platforms and related academic databases.

Platform	Access Type	Open / Closed	Approx. Number of Documents / Records	Status	Short Description
Web of Science	Paid	Closed	90M+	Active	Curated citation index known for quality-controlled indexing and research evaluation use.
Scopus	Paid	Closed	95M+	Active	A large abstract and citation database with wide multidisciplinary coverage.
Google Scholar	Free	Partially Open	300M+	Active	A freely accessible scholarly search engine with very broad coverage across disciplines.
Microsoft Academic Graph	Free	Open	250M+	Discontinued	A large-scale academic graph dataset that is no longer maintained but remains historically important.
Dimensions	Freemium	Partially Open	140M+	Active	Links publications with grants, patents, policy documents, and research metrics.
Crossref / COCI	Free	Open	150M+	Active	Provides DOI-linked metadata and open citation connections for scholarly content.
OpenAIRE	Free	Open	140M+	Active	An open research graph supporting publications, datasets, software, and institutional research visibility.
OpenAlex	Free	Open	250M+	Active	A modern open scholarly knowledge graph and a strong successor to Microsoft Academic Graph.

Note: The document counts above are approximate and may change over time as platforms update their databases.

Quick Understanding

Paid and Closed

Web of Science and Scopus are premium systems with controlled access and strong indexing standards.

Free and Open

OpenAlex, OpenAIRE, and Crossref-based systems are useful for open scholarly data and public access.

Mixed Access

Google Scholar and Dimensions provide wide access, but their openness and feature availability vary.

Historically Important

Microsoft Academic Graph is discontinued, but it played an important role in the development of open academic graphs.

Conclusion

Scholarly Knowledge Graphs are powerful systems for organizing and connecting academic information. They help users explore scholarly communication in a more meaningful way by showing the relationships between papers, authors, institutions, journals, and citations.

In short, SKGs are useful for students, researchers, librarians, and institutions because they make academic knowledge easier to search, understand, analyze, and visualize.