Sebastián Vallejo Vera

About Me

Welcome! I am an Assistant Professor in the Department of Political Science at the University of Western Ontario. I am also a member of the interdisciplinary Laboratory of Computational Social Science (iLCSS) and a Research Fellow at the Hewlett Packard Enterprise Data Science Institute (University of Houston). Previously, I was a Post-Doctoral Fellow in the Department of Political Science at the University of Houston and an Assistant Professor at the Tecnológico de Monterrey, México. I earned my Ph.D. in Political Science from the University of Maryland, College Park.

Research Interest

My research explores the relationship between gendered political institutions and representation, and racial identity and racism in Latin America. I am particularly interested in the gendered barriers in political institutions, and the strategic reaction of political actors when encountering these barriers. My methodological work applies novel Natural Language Processing (NLP) to a wide variety of text data, from legislative speeches to tweets, to answer substantive questions about gender, racism, and politics.

Links to my CV and Google Scholar.

Peer-Reviewed Publications

  1. Timoneda, Joan C., and Sebastián Vallejo Vera. “BERT, RoBERTa or DeBERTa? Comparing Performance Across Transformer Models in Political Science Text.” The Journal of Politics (2025): 87.1 000-000. PDF

  2. Timoneda, Joan C., and Sebastián Vallejo Vera. “Behind the Mask: Random and Selective Masking in Transformer Models Applied to Specialized Social Science Texts.” PloS one (2025): 20.2 e0318421 PDF Replication Material

  3. Alemán, Eduardo, Tiffany Barnes, Juan Pablo Micozzi, and Sebastián Vallejo Vera. “Gender, Institutions, and Legislative Speeches.” Comparative Politics (2025). DOI PDF Replication Material

  4. Alemán, Eduardo, Pablo Valdivieso Kastner, and Sebastián Vallejo Vera. “Speech Targeting and Constituency Representation in Open-List Electoral Systems.” Electoral Studies (2024): 92, 102865. DOI PDF

  5. Hellmueller, Lea, Lindita Camaj, Sebastián Vallejo Vera, and Peggy Lindner. “The Impact of Journalistic Cultures on Social Media Discourse: US Primary Debates in Cross-Lingual Online Spaces.” Digital Journalism (2024): 1-21. DOI PDF

  6. Camaj, Lindita, Lea Hellmueller, Sebastián Vallejo Vera, and Peggy Lindner. “The Democratic Value of Strategic Game Reporting and Uncivil Talk: A Computational Analysis of Facebook Conversations During U.S. Primary Debates”. Journalism & Mass Communication Quarterly (2024): 101(2), 428-450. DOI PDF

  7. Vallejo Vera, Sebastián. “Rage in the Machine: Activation of Racist Content in Social Media.” Latin American Politics and Society (2023): 65(1), 74-100. doi:10.1017/lap.2022.25. DOI PDF

  8. Alemán, Eduardo, Juan Pablo Micozzi, and Sebastián Vallejo Vera. “Congressional Committees, Electoral Connections, and Legislative Speech.” Political Research Quarterly (2022): 10659129221119200. DOI PDF

  9. Abad, Angelica, Raul Aldaz Pena, Diana Davila Gordillo, and Sebastián Vallejo Vera. “An Unwelcomed Deja-vu: Ecuadorian Politics in 2021.” Revista de Ciencia Política 42, no. 2 (2022): 281-308. DOI PDF

  10. Vallejo Vera, Sebastián, and Analía Gómez Vidal. “The politics of interruptions: Gendered disruptions of legislative speeches.” The Journal of Politics 84, no. 3 (2022): 1384-1402. DOI PDF Replication Data Media

  11. Currin, Christopher Brian, Sebastián Vallejo Vera, and Ali Khaledi-Nasab. “Depolarization of echo chambers by random dynamical nudge.” Scientific Reports 12, no. 1 (2022): 1-13. DOI PDF

  12. Abad Cisneros, Angélica, Raúl Aldaz Peña, Diana Dávila Gordillo, and Sebastián Vallejo Vera. “Believe in me: parties’ strategies during a pandemic, evidence from Ecuador.” Journal of Politics in Latin America 13, no. 3 (2021): 419-441. DOI PDF

  13. Timoneda, Joan C., and Sebastián Vallejo Vera. “Will I die of coronavirus? Google Trends data reveal that politics determine virus fears.” Plos one 16, no. 10 (2021): e0258189. DOI PDF Media

  14. Calvo, Ernesto, Paula Clerici, and Sebastián Vallejo Vera. “Ciencia y política en tiempos del covid-19.” Política y gobierno 28, no. 2 (2021). HTTP PDF

  15. Timoneda, Joan C., and Sebastián Vallejo Vera. “How do shocks realign interest group lobbying in congress? Evidence from Ecuador.” The Journal of Legislative Studies (2021): 1-39. DOI PDF

  16. Vallejo Vera, Sebastián. “By invitation only: On Why Do politicians bring interest groups into committees.” The Journal of Legislative Studies (2021): 1-38. DOI PDF

  17. McDermott, Monika L., Douglas Schwartz, and Sebastian Vallejo Vera. “Talking the talk but not walking the walk: Public reactions to hypocrisy in political scandal.” American Politics Research 43, no. 6 (2015): 952-974. DOI PDF

Book Chapters

  1. Vidal, Analía Gómez, and Sebastián Vallejo Vera, ‘Ecuador: Individual Incentives and the Gendered Path to Power’, in Hanna Back, Marc Debus, and Jorge M. Fernandes (eds), The Politics of Legislative Debates (Oxford, 2021; online edn, Oxford Academic, 18 Nov. 2021), DOI PDF

Books

  1. Vallejo Vera, Sebastián. 2018. Angostura, 30-S y la (re)militarización de la seguridad interna en Ecuador. Corporación Editora Nacional – Ecuador: 978-9978-84-997-2. PDF

Working Papers

  1. Vallejo Vera, Sebastián and Hunter Driggers. “Bias in LLMs as Annotators: The Effect of Party Cues on Labelling Decision by Large Language Models.” (2025). arXiv preprint arXiv:2408.15895. PDF (R&R at Humanities and Social Sciences Communications - Nature)

  2. Dávila Gordillo, Diana, Joan C. Timoneda, and Sebastián Vallejo Vera. “Machines Do See Color: How Transformers Outperform Other Approaches in Classifying Overt and Covert Racism in Text.” (2024). arXiv preprint arXiv:2401.09333. PDF (R&R at Sociological Methods and Research)

  3. Dávila Gordillo, Diana and Sebastián Vallejo Vera. “Gender Quotas and Woman Candidates”. (Under Review)

  4. Timoneda, Joan C., and Sebastián Vallejo Vera. “Memory Is All You Need: Testing How Model Memory Affects LLM Performance in Annotation Tasks.” arXiv preprint arXiv:2503.04874 (2025). (Under Review)

  5. Vallejo Vera, Sebastián. “Performance of Maximum Likelihood Fixed Effects Estimation in Panel Data with Sample Selection Bias.” Under Review

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