Lawrence R. Klein and the making of large-scale macro-econometric modeling, 1938-1955

Lawrence R. Klein was the father of macro-econometric modeling, the scientific practice that dominated macroeconomics throughout the second half of the twentieth century. Therefore, understanding how Klein developed his identity as a macro-econometrician and how he conceived and forged macro-econometric modeling at the same time, is essential to draw a clear picture of the origins and subsequent development of this scientific practice in the United States. To this aim, I focus on Klein’s early trajectory as a student of economics and as an economist (from 1938-1955), and I particularly examine the extent to which the people and institutions Klein encountered helped him shape his professional identity. Klein’s experience at places like Berkeley, MIT, Cowles, and the University of Michigan, as well as his early acquaintance with people such as Griffith Evans, Paul Samuelson, and Trygve Haavelmo were decisive in the formation of his idea on how econometrics, expert knowledge, mathematical rigor, and a specific institutional configuration should enter macro-econometric modeling. Although Klein’s identity defined some of the most important characteristics of this practice, by the end of the 1950s, macro-econometric modeling became a scientific practice independent of Klein’s enthusiasm and with a “life of its own,” ready to be further developed and adapted to specific contexts by the community of macroeconomists.