Andrew Leigh would take a daily a multivitamin, he says, until he learned that a randomized controlled trial, or RCT, found no increase in lifespan linked to taking them. So he stopped. Leigh isn’t a nutritionist, he’s an economist. But more to the point, Leigh is also an unrepentant ‘randomista,’ which is what he calls researchers who use RCT’s to tackle thorny issues of public concern. (Leigh is also a politician, 2010 sitting since as the member of Australia’s Parliament for the Division of Fenner, a Canberra suburb.)

The word ‘randomista,’ Leigh tells interviewer David Edmonds in this Social Science Bites podcasts, was coined by Nobel laureate Angus Deaton (also a Bites alumnus)  “as “a term almost of abuse – but I’ve turned it into a compliment!” (It’s also the title of his new book, Randomistas: How Radical Researchers Are Changing Our World.)

“Deaton had noticed that there were randomized trials proliferating across development economics,” Leigh explains, “and felt that in some areas they were becoming almost theory-free. I think it’s perhaps a reasonable criticism in some parts of development economics, but certainly for most questions, I think we’re doing too few randomized trials instead of too many.”

For Leigh, the proper definition of a randomista is “someone who believes we can find answers to important questions by tossing a coin and putting people into a treatment and control group, comparing the outcome, and then using the randomization to get a true causal effect.”

Randomized controlled trials have been used for years in drug testing, but are increasingly being used in business, crime prevention, education and social science. The origin of RCTs is a matter of some dispute, but Leigh uses the scurvy trials of James Lind, whose apples-to-apples comparison of various anti-scorbutic therapies in vogue in the 18th century allowed the Royal Navy to beat its most deadly enemy – yes Bonaparte, but in reality scurvy itself.

These days, RCTs are used as much to kill bad policies as they are to save lives. Leigh offers a litany of popular social programs that actual research demonstrated had the opposite effect of what they intended. For example, trials showed the Scared Straight program not only didn’t keep nonserious juvenile offenders from committing more serious crimes, it may have increased the odds they would. Other RCTs showed that while microcredit has some benefits, it doesn’t seem to improve household income, keep kids in school or improve women’s lot in life.

“Randomized trials are where scientific literacy meets modesty,” Leigh quips.

There are, of course, success stories, too, and Leigh cites drug courts and restorative justice as two public safety wins endorsed by RCTs. Leigh even used an RCT himself in naming his book, buying ads with various titles on Google to fine which resonated most. Total cost? About $50 and an hour of effort.

“I am aware that I look a little bit like a man with a hammer ranging around hoping to find nails. If you want to know about the impact of denuclearization on the Korean peninsula, a randomized trial is probably not your best way of working it out. But there are surprising areas in which you can figure things out.”

Before Leigh ran for Parliament Leigh was a professor at the Australian National University. He is a graduate of the University of Sydney and a fellow of the Australian Academy of Social Sciences. His books include Disconnected (2010), Battlers and Billionaires (2013), The Economics of Just About Everything (2014), The Luck of Politics (2015), and Choosing Openness: Why Global Engagement is Best for Australia (2017).