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, Google Scholar, and  GitHub.

Peer-Reviewed Publications

  1. Timoneda, J. C., & Vallejo Vera, S. (2026). Rolling memory: A new approach to annotation with generative LLMs in social and political research. Chinese Political Science Review, 1–15. PDF

  2. Vallejo Vera, S., Timoneda, J. C., & Dávila Gordillo, D. (in press). Machines do see color: Using LLMs to classify overt and covert racism in text. Sociological Methods & Research. arXiv:2401.09333. PDF Replication Material

  3. Vallejo Vera, S., & Driggers, H. (2025). LLMs as annotators: The effect of party cues on labelling decisions by large language models. Humanities and Social Sciences Communications, 12(1), 1–11. PDF

  4. Timoneda, J. C., & Vallejo Vera, S. (2025). BERT, RoBERTa or DeBERTa? Comparing performance across Transformer models in political science text. The Journal of Politics, 87(1), 347–364. PDF Replication Material

  5. Timoneda, J. C., & Vallejo Vera, S. (2025). Behind the mask: Random and selective masking in Transformer models applied to specialized social science texts. PLOS ONE, 20(2), e0318421. PDF Replication Material

  6. Alemán, E., Barnes, T., Micozzi, J. P., & Vallejo Vera, S. (2025). Gender, institutions, and legislative speeches. Comparative Politics, 57(2), 219–241. DOI PDF Replication Material

  7. Alemán, E., Valdivieso Kastner, P., & Vallejo Vera, S. (2024). Speech targeting and constituency representation in open-list electoral systems. Electoral Studies, 92, 102865. DOI PDF

  8. Hellmueller, L., Camaj, L., Vallejo Vera, S., & Lindner, P. (2024). The impact of journalistic cultures on social media discourse: US primary debates in cross-lingual online spaces. Digital Journalism, 1–21. DOI PDF

  9. Camaj, L., Hellmueller, L., Vallejo Vera, S., & Lindner, P. (2024). 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, 101(2), 428–450. DOI PDF

  10. Vallejo Vera, S. (2023). Rage in the machine: Activation of racist content in social media. Latin American Politics and Society, 65(1), 74–100. DOI PDF

  11. Alemán, E., Micozzi, J. P., & Vallejo Vera, S. (2022). Congressional committees, electoral connections, and legislative speech. Political Research Quarterly. DOI PDF

  12. Abad, A., Aldaz Peña, R., Davila Gordillo, D., & Vallejo Vera, S. (2022). An unwelcomed deja-vu: Ecuadorian politics in 2021. Revista de Ciencia Política, 42(2), 281–308. DOI PDF

  13. Vallejo Vera, S., & Gómez Vidal, A. (2022). The politics of interruptions: Gendered disruptions of legislative speeches. The Journal of Politics, 84(3), 1384–1402. DOI PDF Replication Data Media

  14. Currin, C. B., Vallejo Vera, S., & Khaledi-Nasab, A. (2022). Depolarization of echo chambers by random dynamical nudge. Scientific Reports, 12(1), 1–13. DOI PDF

  15. Abad Cisneros, A., Aldaz Peña, R., Dávila Gordillo, D., & Vallejo Vera, S. (2021). Believe in me: Parties’ strategies during a pandemic, evidence from Ecuador. Journal of Politics in Latin America, 13(3), 419–441. DOI PDF

  16. Timoneda, J. C., & Vallejo Vera, S. (2021). Will I die of coronavirus? Google Trends data reveal that politics determine virus fears. PLOS ONE, 16(10), e0258189. DOI PDF Media

  17. Calvo, E., Clerici, P., & Vallejo Vera, S. (2021). Ciencia y política en tiempos del covid-19. Política y gobierno, 28(2). HTTP PDF

  18. Timoneda, J. C., & Vallejo Vera, S. (2021). How do shocks realign interest group lobbying in congress? Evidence from Ecuador. The Journal of Legislative Studies, 1–39. DOI PDF

  19. Vallejo Vera, S. (2021). By invitation only: On why do politicians bring interest groups into committees. The Journal of Legislative Studies, 1–38. DOI PDF

  20. McDermott, M. L., Schwartz, D., & Vallejo Vera, S. (2015). Talking the talk but not walking the walk: Public reactions to hypocrisy in political scandal. American Politics Research, 43(6), 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. Dávila Gordillo, Diana and Sebastián Vallejo Vera. “Gender Quotas and Woman Candidates”. (Under Review)

  2. 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)

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

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