This article explores Robert E. Lucas’s policy agenda and his engagement with the public debate between the 1970s and early 1980s. It investigates how he interacted with the public debate by envisioning key principles of his macroeconomic theory and methodology, and how he promoted his policy agenda. An exploration of Lucas’s personal and professional archives sheds light on his participation in policy debates after the publication of his works, illustrating how Lucas built a discreet and cautious way of engaging with the public. Lucas did not propose a detailed program to implement his policy agenda, nor was he actively promoting his policy agenda. The article suggests that Lucas’s originality compared to his contemporaries was his belief on the ability of macroeconomics to scientifically devise binding policy rules that could be integrated in an economic constitution.
The article shows that Sargent’s macroeconomic vision differs from Lucas' one. For the latter, the assumptions of a model are “un-realistic”, i.e., the model does not aim to represent reality. It is a simulation tool that allows the assessment of different economic policies. The “Lucasian” ideal is a macroeconomist, who is therefore destined to become an engineer in charge of providing public authorities with an “economic policy software”. The engineer uses this software to guide policymakers on a scientific basis. For its part, Sargent considers that in order to substitute the Keynesian paradigm, the new classical economics must be able to fulfill the same tasks. And one of these tasks is to advise public authorities by providing them with an interpretative framework for the economic and social phenomena and with intuitive tools to discuss the economic policies that will be set up. Sargent wants to apply what he calls the Rational Expectations Theory to a set of concrete events (Poincaré stabilization, German hyperinflation, Thatcher and Reagan policies) in order to demonstrate the relevance of this interpretative framework used to think about contemporary economic problems.