Lant Pritchett’s fondest 10th birthday wishes to the Poverty Action Lab:

The delightfully quirky aspect of the success of the randomista movement is that it was, and remains, entirely faith-based.

…The claim that attracted resources and support from development organizations and attention from the press was the claim that “rigorous” evidence from these RCTs could, should, and would produce better development projects and policies and, hence, ultimately better outcomes for human beings.

…The randomistas were not proposing new methods or techniques but rather broader adoption into the field of development methods that already had a long history. There was a big fad toward the use of experiments in a variety of social policy domains in the USA in the 1970s.

…Strangely, whether or not decades of social policy RCTs actually did have impact on policies and outcomes in the USA just kind of never came up in arguing that they would in developing countries.

In blogger camp they say “never feed the trolls”, but since Lant is my favorite development troll, I cannot resist. Even if I should be reading someone’s dissertation at the moment.

This week I’m teaching about the politics of foreign aid. Lant’s timing is excellent. I’m having students watch his lecture on how aid is like bad ballet recitals.

His point is this: you need a lot of really, really bad ballet to produce one prima donna. The pinnacle of the art isn’t possible without tens of thousands of 10-year olds doing crappy pirouettes.

As with ballet is development: you need lots of mediocre ideas for the great ones to emerge–the ones that change the world. His example: India in 1992, in the midst of a financial crisis, tips its macroeconomic policy in a liberal direction, helping set the country on a path of unprecedented growth. That one move was, he imagines, partly the result of years of practice, of theory, of trial and error. This one move reduced so much poverty that even if the only thing every development project in history did was make that one moment happen, it was worth it.

Now, the only problem with this story is that Great Moments in Centralized Decision Making Based On Economic Ideologies also brought us hits such as “The Great Leap Forward”. So we have to amend the lesson a little: if all the development projects and research in history brought us slightly closer to tipping the less disastrous way in moments of crisis, then it was all worthwhile.

I can get behind that. And I have to say that some of projects and evidence that make me hopeful about the future include randomized control trials. I don’t expect policymakers to quote the latest trials and suddenly convert to evidence based decisions. But I do expect the evidence to infiltrate the way economics is taught, the way policy is talked about, and the received wisdom. This might take years or decades. Sometimes it will happen quickly, the way that the wind has fallen out of the sails of micro-finance and filled those of cash transfers.

Yes, this is a faith-based belief. So is any prediction of the future. Most of the most interesting trials haven’t been run yet. And it’s always faith based to suppose politicians will put hard facts above, well, politics. But there’s some basis to my hope.

Take this paper by David Weil. He looks at decades of evidence on health interventions and development. The slow accumulation of evidence from many trials suggests that making people healthier might make nations poorer in the very short run (since there’s the same amount of wealth but more people). But in the longer run there are small, positive returns to wages and productivity. These gains are larger than some economists would argue (such as Daron Acemoglu and James Robinson) but smaller than others would have us believe (such as Jeff Sachs and the World Health Organization). Terrific. This is important stuff. And I think it will infiltrate thinking in the field.

When the randomistas run their revivals, some start speaking in tongues and juggling snakes. I think, for the most part, they do this deliberately–because they’re skillful politicians and know that nuanced messages don’t make for policy change. And if a little populist evangelism will get more evidence-based thinking in the world, and tip us marginally further from Great Leaps Forward, I have one thing to say: Hallelujah.