As early as the mid-1950s, Dr. Meier was one of the first and most vocal proponents of what is called “randomization.”
Under the protocol, researchers randomly assign one group of patients to receive an experimental treatment and another to receive the standard treatment. In that way, the researchers try to avoid unintentionally skewing the results by choosing, for example, the healthier or younger patients to receive the new treatment.
If the number of subjects is large enough, the two groups will be the same in every respect except the treatment they receive. Such randomized controlled trials are considered the most rigorous way to conduct a study and the best way to gather convincing evidence of a treatment’s effects.
Before randomization, the science of clinical trials was imprecise. Researchers, for example, would give a new treatment to patients who they thought might benefit and compare the outcomes to those of previous patients who were not treated, a method that could introduce serious bias.
The article rightly focuses on Meier's influence in medicine, but the influence of the randomized trial on modern economics (and the applied social sciences in general) cannot be overstated. The observation that randomization lets one link correlation to causality as opposed to simple association is the basis of much of modern econometrics, and the framing and intellectual architecture built upon that insight has provided a host of very important results. Everything from Freakonomics' popularization of applied microeconomics to the ongoing row in the development community between the highly successful "randomistas" and their critics can be viewed as stemming from Meier and his allies' attempts to make medical research robust. While randomization clearly isn't everything, and even a well-identified research strategy must be subject to a host of caveats, if you're following this blog, doing applied work yourself, or just generally care about empirically determined (as opposed to theoretically justified) policy, you might want to raise a glass tonight to Meier and his legacy.