He used aggregate data from U.S. crop-reporting districts and states, and hence, could not claim
that similar results would obtain when individual farmers were the units of analysis. Griliches (1957) concluded: "It is my belief that in the long run, and cross-sectionally, [sociological] variables tend to cancel themselves out, leaving the economic variables as the major determinants of the pattern of technological change." Griliches' strong assertion of the importance of profitability as a sole explana-
tion of rate of adoption is consistent with the "Chicago School" of economists, who assume that, in the absence of evidence to the con- trary, the market works.