If you answered “Probably Esther Duflo, sometime in the early 2000s?” just as I did, you were wrong, just as I was.<\/p>\n
As it turns, Immink and Viteri were the first to use randomization in a two-part article (part 1 is here<\/a>; part 2 is there<\/a>)\u00a0testing the efficiency wage hypothesis published in the Journal of Development Economics<\/em> in 1981:<\/p>\n This study represents an empirical test of the productivity consumption relation of the efficiency wage hypothesis, which is briefly discussed here. The research setting and design of the study are described. An energy supplementation program was generally effective in raising the daily energy intake and energy expenditure levels of Guatemalan sugarcane workers who were moderately energy deficient. Increased energy availability did not result in increased energy expenditure at work, or in an increased supply of work units. The results do not provide evidence of a strong productive-energy intake relationship among these workers.<\/p><\/blockquote>\n Now, their randomization was not perfect, which they acknowledge themselves: they would have liked to assign individual workers to the high-energy treatment group at random, but instead decided to assign pre-existing groups of workers (which were not formed randomly) to the treatment and control groups.<\/p>\n Still, it is fascinating to see that randomization and the notion of internal validity were discussed in development economics\u00a0more than thirty years ago, and that it took the field a good 20 years to rediscover randomization. This is similar to how Herman Wold<\/a>\u00a0was the first to take\u00a0the idea of causality seriously in economics\u00a0in 1945, yet it wasn’t until much later that economists followed suit.<\/p>\n