CMU-S3D-26-106
Software and Societal Systems Department
School of Computer Science, Carnegie Mellon University



CMU-S3D-26-106

Misinformation on Search Engines:
Networked Characterization and Identification

Evan M. Williams

April 2026

Ph.D. Thesis
Societal Computing

CMU-S3D-26-106.pdf


Keywords: Search Engines, Web Search, SEO, Data Voids, Information Gaps, RAG, GNN, Web Graph, Misinformation

I explore how misinformation spreads through websearch, with a focus on how and why unreliable websites can rank highly in search engines. I additionally introduce models that can help search engines improve the reliability of search results. I first explore the limitations of Google's current efforts to combat low-reliability and low-relevance content in its search engine. I then demonstrate both how owners of unreliable websites can manipulate structural authority patterns present in the webgraphs, and introduce content-agnostic Graph Neural Networks to detect unreliable websites using these signals. I then explore the content-based approaches that unreliable websites use to rank on search engines and again propose models for detecting them. I also explore how the presence of unreliable websites on SERPs impacts Google's AI overviews. I then combine the content and webgraph with social media mentions of unreliable websites to create a realistic model of the paths that users can take to reach an unreliable website in hopes of better understanding the signals present in each. Finally, I combine the takeaways from the previous chapters into a conceptual framework that will be integrated into a simulated information environment exercise, where misinformation experts will use the work developed in this thesis to characterize and identify misinformation and narratives.

202 pages

Thesis Committee:
Kathleen M. Carley (Chair)
Uttara Ananthakrishnan
Jamie Callen
Francesca Tripodi (The University of North Carolina at Chapel Hill)

Nicolas Christin, Head, Software and Societal Systems Department
Martial Hebert, Dean, School of Computer Science


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