1. Clinical Trials
The concept of a control and experimental group was introduced in 1747 by James Lind when he demonstrated the benefits of citrus fruits in preventing scurvy using a scientific experiment.1 As a result of his work, Lind is considered to be the father of clinical trials. The method of randomly assigning subjects to control and treatment groups, however, was not developed until the 1920s.
2. Agricultural Experiments
Randomization was introduced to scientific experimentation in the 1920s when Neyman and Fisher conducted the first randomized trials in separate agricultural experiments. Fisher’s field experimental work culminated with his landmark book, The Design of Experiments, which was a main catalyst for the much of the growth of randomized evaluations.2
3. Social Programs
Randomized trials were introduced to government sponsored social experiments between 1960 and 1990. Rather than small-scale experiments conducted on plants and animals, these new social experiments were significantly larger in scale and focused on people as the subjects of interest. The idea of conducting social policy experiments grew out of a 1960s debate over the merits of the welfare system. The model of social experimentation was later applied both in Europe and the United States to evaluate other programs such as electricity pricing schemes, employment programs, and housing allowances. Since then social experiments have been used across disciplines and in a variety of settings around the world to guide policy decisions.3
The Abdul Latif Jameel Poverty Action Lab (J-PAL) was founded in June 2003 as a network of affiliated professors around the world who are united by their use of randomized evaluations to answer questions critical to poverty alleviation.
1 Thomas, Duncan P. Sailors, Scurvy and Science. Journal of the Royal Society of Medicine. 90 (1997).
2 Levitt, Steven D. and John A. List. 2009. “Field Experiments in Economics: The Past, The Present, and The Future.” European Economic Review 53(1): 1-18.