Traditional estimates of prewar GNP exaggerate the size of cycles because they are based on the assumption that GNP moves approximately one for one with commodity output valued in producer prices. This paper derives new estimates of GNP for 1869-1908 using an estimate of the actual relationship between GNP and commodity output. This estimated relationship is allowed to be time-varying and is derived from a regression covering the periods 1909-28 and 1947-85. The new estimates of GNP indicate that there has been much less stabilization between the prewar and postwar eras than is conventionally believed.

This paper shows that the existing estimates of prewar gross national product exaggerate the size of cyclical fluctuations. The source of the exaggeration is that the original Kuznets estimates are based on the assumption that GNP moves one-for-one with commodity output valued at producer prices. New estimates of GNP for 1869-1918 are derived using the estimated aggregate relationship between GNP and commodity output for the interwar and postwar eras. The new estimates of GNP indicate that the business cycle is only slightly more severe in the pre-Worid War I era than in the post-World War II era.