A Tribute to Jean-Pierre Laffargue

Posted on 04 April 2025

Jean-Pierre Laffargue passed away on March 15, 2025. The team of macroeconomists at CEPREMAP wished to pay tribute to this colleague, who was also, for many of us, our professor.

Jean-Pierre Laffargue leaves an indelible mark on CEPREMAP’s macroeconomic activities. His commitment to developing numerical methods for solving large-scale, nonlinear, perfect foresight economic models was instrumental for the international community of macroeconomists. It was during the 1980s that Jean-Pierre Laffargue decided to develop an algorithm capable of solving any type of nonlinear dynamic model. His key contribution lay in harnessing the superior speed and stability of the Newton-Raphson algorithm, while devising ways to minimize memory requirements for its practical implementation, thereby reducing computational time. Laffargue’s algorithm was first published in 1988 in CEPREMAP’s Couvertures Oranges series, and later in 1990 in the Annales d’Économie et de Statistique. Around this major breakthrough in numerical methods for economists, the Dynare software was built. Laffargue’s algorithm is now used daily by macroeconomists around the world—whether academic researchers or economists at major institutions such as the IMF, the Federal Reserve System, the ECB, and others. His foundational research continues to contribute to public policy by enabling the use of state-of-the-art macroeconomic analysis to assess and compare alternative policy scenarios.

Building on these methodological achievements, Jean-Pierre Laffargue also contributed to the debate on the effectiveness of public policy in France. Initiating what would become the CEPREMAP tradition, he developed original models of the French economy, making it possible to analyze and evaluate a wide range of reforms. His work significantly shaped the analytical frameworks used in policy decision-making. In particular, during the 1990s (1993, 1995, 1996a, 1996b), Laffargue demonstrated how to integrate the latest advances in macroeconomic theory—such as monopolistic competition and wage bargaining—into dynamic models, even as these theoretical developments were still fresh in the literature. The models he developed were subsequently used to evaluate a broad array of public policies in France, including payroll tax cuts on low wages in response to skill-biased technological change, social VAT, and the taxation of capital income.

Jean-Pierre Laffargue was also a teacher to many of us. In this role, we are grateful to him for instilling in us a sense of rigor and critical thinking. His humor, love of debate, and attentive listening made it easy to engage with him and to learn from his teachings—both inside and outside the classroom.

References

  • Laffargue, Jean-Pierre. 1988. Résolution d’un modèle macroéconomique non linéaire avec anticipations rationnelles. Document de travail du CEPREMAP, no. 88/24. Paris: CEPREMAP.

  • Laffargue, Jean-Pierre. 1990. Résolution d’un modèle macroéconomique avec anticipations rationnelles. Annales d’économie et de statistique, 17: 97-119.

  • Laffargue, Jean-Pierre. 1993. Maquette dynamique de l’économie française avec anticipations rationnelles, concurrence monopolistique et négociations sur le marché du travail. Document de travail du CEPREMAP, no. 88/24. Paris: CEPREMAP.

  • Laffargue, Jean-Pierre. 1995. A Dynamic Model of the French Economy, with Rational Expectations, Monopolistic Competition and Labour Market Bargaining. Annales d’économie et de statistique, 37/38: 465-530.

  • Laffargue, Jean-Pierre. 1996a. Chômage des non qualifiés et progrès technique. le modèle charlotte. Document de travail du CEPREMAP, no. 96/12. Paris: CEPREMAP

  • Laffargue, Jean-Pierre. 1996b. Fiscalité, Charges sociales, qualifications et emploi. Économie et Prévision, 125: 87-105.