”Reductionist science” and development

I like two things in particular about Chris Blattman’s response to Aid Watch’s diatribe against Millenium Villages.

First, he does a great job of concisely synthesizing the opposing philosophies on development (Sachs vs. Easterly, if you will):

We wouldn’t be testing the fundamental premises: the theory of the big push; that high levels of aid simultaneously attacking many sectors and bottlenecks are needed to spur development; that there are positive interactions and externalities from multiple interventions.

The alternative hypothesis is that development is a gradual process, that marginal returns to aid may be high at low levels, and that we can also have a big impact with smaller, sector-specific interventions.

Second, he nails the flaw in the simplistic critique that MVs prove nothing because they’re not subject to rigorous evaluation (e.g. randomized impact evaluations):

To test the big push and all these externalities, we’d need to measure marginal returns to many single interventions as well as these interventions in combination (to get at the externalities). I’m not sure the sample size exists that could do it.

This reminds me of Michael Pollan’s critique of “reductionist science” in nutrition in his books – single development treatments (or nutrients) can be tested in isolation, but what if they have complex interactions with one another? The combinatorial explosion of trials you’d need to rigorously test all of these interactions renders the traditional scientific method helpless to mortals.

This, in turn, reminds me of business. Good businesspeople have no illusions that they’ll ever have rigorous certainty that they are making the right decision; but they have to make those decisions anyway.

How to apply this to development, I’m not sure (after all, “who decides who decides?”), but the reductionist science analogy was a new thought that I was excited to share.