Jim Manzi, founder and chair of Applied Predictive Technologies, senior fellow at the Manhattan Institute, and author of Uncontrolled, talks with EconTalk host Russ Roberts about the Oregon Medicaid study and the challenges of interpreting experimental results. Manzi notes a number of interesting aspects of the study results that have generally been unnoticed--the relatively high proportion of people in the Oregon study who turned down the chance to receive Medicaid benefits, and the increase (though insignificant) in smoking by those who received Medicaid benefits under the experiment. Along the way, Manzi discusses general issues of statistical significance, and how we might learn more about the effects of Medicaid in the future.
Jim Manzi, author of Uncontrolled, talks with EconTalk host Russ Roberts about the reliability of science and the ideas in his book. Manzi argues that unlike science, which can produce useful results using controlled experiments, social science typically involves complex systems where system-wide experiments are rare and statistical tools are limited in their ability to isolate causal relations. Because of the complexity of social environments, even narrow experiments are unlikely to have the wide application that can be found in the laws uncovered by experiments in the physical sciences. Manzi advocates a trial-and-error approach using randomized field trials to verify the usefulness of many policy proposals. And he argues for humility and lowered expectations when it comes to understanding causal effects in social settings related to public policy.