An Institutionalist's Journey into the Years of High Theory: John Maurice Clark on the Accelerator-Multiplier Interaction

A few years ago, an article by Arnold Heertje and Peter Heemeijer (2002) triggered an articulate and stimulating debate among scholars on the intellectual origins of Paul Samuelson's multiplier-accelerator model (1939a, 1939b). The discussion, which involved the participation of Samuelson himself, centered on whether, and to what extent, Samuelson's 1939 seminal contributions were inspired by Roy Harrod's The Trade Cycle (1936). Heertje and Heemeijer argue that “there is little factual support for Samuelson's suggestion ascribing the model mainly to Alvin Hansen, his mentor in the days of the creation of the model” (Heertje and Heemeijer 2002, p. 207). Instead, they provide convincing evidence indicating that it was Roy Harrod who actually played the major role in developing the ideas leading to the multiplier-accelerator interaction. “Theoretically speaking,” they assert, “it was Harrod who provided the most important contribution to the model. His interesting 1936 work The Trade Cycle contained valuable ideas regarding the combination of the multiplier and accelerator” (p. 217).