A Model to “Make Decisions and Take Actions†: Leif Johansen’s Multisector Growth Model, Computerized Macroeconomic Planning, and Resilient Infrastructures for Policymaking

The 1960s were the glorious age of large-scale, “economy-wide†macroeconometric models, which enabled forecasts and simulations of the quantitative effects of certain policy changes within systems of simultaneous equations. This article is concerned (1) with the form and character of the kind of knowledge these models brought about; and (2) with the ways in which these models shaped the practices, objects, and the very notion of macroeconomic planning. The concepts of bricolage and infrastructure help to account for the continuous reciprocal shaping of mathematical techniques, empirical data, bits of economic theory, institutional arrangements, the aims and hopes of economic planning, images and visions of the economy, and the practical requirements and affordances of computing technologies. The article traces the movements and changes of the multi-sector growth model, constructed by the Norwegian economist and communist Leif Johansen, from its publication in 1960 to its implementation in national macroeconomic planning and its wider circulation under the label of “computable general equilibrium models.†In Norway, it became one component of a “system of models,†which, far from simply being a passive “tool for decision making,†structured bureaucratic procedures, and formatted the basic concepts of policymaking. In contrast to stories of big theoretical breaks and shifts in economic ideas in the 1970s, the paper finally asks for the continuities of so-called applied models, which were constructed in the postwar period, based on prewar visualizations of the eonomy, and which remain active until the present day.