Thanks for the comment. Check out the first part of our reply to the MVP, where we tried to address this issue: http://blogs.worldbank.org/africacan/evaluating-the-millennium-villages-reply-to-the-mvp-upcoming-seminar-with-comments-from-jeff-sachs Fundamentally, for any impact evaluation, the relevant question is what would have happened in the counterfactual, i.e. if the project/intervention had never taken place. We argue that what took place in country as a whole (or, as an alternative, the area around the MVP site) during the MVP period is a reasonable, though imperfect, estimate of the counterfactual of the MVP. The fact that some other interventions that are similar to some components of the MVP, e.g. provision of subsidized fertilizer, may have taken place in other places is entirely irrelevant for estimating the *effects of the MVP package*, which is the question at hand. That's because those interventions would have taken place even if the MVP had never existed.