Do people change their use of prescription medications when cannabis becomes a legal alternative? Father–daughter research team W. David Bradford and Ashley Bradford, from the University of Georgia, trawled through the data to uncover the truth, and their findings could play a part in the rescheduling of medical cannabis – as well as speaking volumes about public opinion.

The Bradfords analyzed data on prescription drug use in the US from 2010 to 2013, focusing specifically on patients covered by Medicare Part D, the federal government program that subsidizes prescription drugs for people over 65 – an age range thought to be most opposed to using cannabis. “It was a question of robustness,” says David Bradford, Adjunct Professor in the Department of Economics. “We had good data on Part D drug use, and believed that if we found an effect we could be confident that it was real. Ultimately, we were surprised at how statist ically significant and robust the results were.”