Guertin JR, Conombo B, Langevin R, et al. A Systematic Review of Methods Used for Confounding Adjustment in Observational Economic Evaluations in Cardiology Conducted between 2013 and 2017. Medical Decision Making. 2020;40(5):582-595. doi:10.1177/0272989X20937257

Langevin, R. (2025). Policy Learning with Observational Data: The Case of Hepatitis C Treatment for HIV/HCV Co-Infected Patients (Job Market Paper)

Abstract: Decision-makers often must select a single option from a finite set of alternatives: physicians choose a medical treatment, investors select a risk level for their portfolio, and insurers set a premium for an insurance policy. In the hope of achieving better outcomes, policymakers sometimes provide policy rules or guidelines to direct such decisions. In this paper, I show how to design an optimal policy rule using observational data under relatively weak assumptions about the underlying structure of the heterogeneous sampled population. Consistent estimation of conditional average treatment effects is performed via a weighted K-means algorithm, assuming that the outcome model is correctly specified within each group of homogeneous observations. Feasible optimal policy rules are implemented through a standard decision tree under both perfect and imperfect adherence to treatment. This methodology is applied to the case of treatment choice for Hepatitis C (HepC) in patients co-infected with the human immunodeficiency virus (HIV) and the HepC virus (HCV), a setting where there is no uniform guideline regarding modern pharmaceutical treatment options. Estimation results show that one group of patients has an approximate 80% chance of spontaneously clearing HCV without any treatment. Estimation results also show that reallocating treatments among treated individuals could have reduced total treatment costs by between CAN$2.7 million and CAN$3.3 million, while slightly increasing total health benefits under either perfect or imperfect adherence to treatment compared to the status quo. Improved guideline recommendations for the management of HIV/HCV co-infected patients can be easily derived using the proposed methodology.

Langevin, R. (2025). Bias-Reduced Estimation of Finite Mixtures: An Application to Latent Group Panel Structures

Ammi, M., Langevin, R., Strumpf, E. C., & Arpin, E. (2024). Effets de la pandémie de COVID-19 sur la réallocation des dépenses de santé publique par fonction : estimation de court terme et analyse prédictive contrefactuelle (2024RP-11, Rapports de projets, CIRANO. In French.) https://doi.org/10.54932/LSLR2977

Ammi, M., Langevin, R., Strumpf, E. C., & Arpin, E. (2024). S’attaquer aux crises épidémiologiques : oui, mais à quel prix ? (2024PJ-07, Revue PERSPECTIVES, CIRANO. In French.) https://doi.org/10.54932/TUPX6305

Langevin, R., Couturier, E. (2023). Spirale salaires-inflation: mythe ou réalité? Institut de recherche et d’informations socioéconomiques (IRIS).

Devin N., Langevin R. (2022), Market Basket Measure Research: Additional Income Inequality Indicators using the Market Basket Measure, Income Research Paper Series, Statistics Canada, Catalogue no. 75F0002M

Langevin, R. (2019). Les projets de loi sur la laïcité augmentent-ils le nombre de crimes haineux au Québec? Ligue des droits et libertés, section Québec.