WWID: An Experimental Approach

In Chapter 2 of What Works in Development, Dani Rodrik (who has sadly stopped blogging) argues that 1), we shouldn't consider RCTs superior to other types of studies, because while they have strong internal validity they often have weak (and unacknowledgedly so) external validity (and other studies can be stronger on external validity), and 2), there is a philosophical convergence on "experimentalism" between micro development economists (e.g. the randomistas) and macro development economists, who now think much more in terms of diagnostics and testing to find binding constraints on economic growth than the previous worldview which came with an a priori vision of what works (e.g. the Washington Consensus).

Then there are two short commentaries:

• Sendhil Mullainathan sees a divergence instead of a convergence (with the macro guys willing to make sweeping recs, and the micro guys only willing to make "guarded statements" about very specific interventions)


• Martin Ravaillon argues that the internal validity of RCTs is less ironclad than advertised because of omitted variables like selective participation, other actors (e.g. gov't shifts resources toward control villages, etc.)