Title: The illusion of sustainability
Description: "The history of foreign development assistance is one of movement away from addressing immediate needs and toward focusing on the underlying causes of poverty.  A recent manifestation is the move towards sustainability,' which stresses community mobilization, education, and cost-recovery.  This stands in contrast to the traditional economic analysis of development projects, with its focus on providing public goods and correcting externalities.  We examine evidence from randomized evaluations on strategies for combating intestinal worms, which affect one in four people worldwide.  Providing medicine to treat worms was extremely cost effective, although medicine must be provided twice per year indefinitely to keep children worm-free.  An effort to promote sustainability by educating Kenyan schoolchildren on worm prevention was ineffective, and a mobilization' intervention from psychology failed to boost deworming drug take-up.  Take-up was highly sensitive to drug cost: a small increase in cost led to an 80 percent reduction in take-up (relative to free treatment).  The results suggest that, in the context we examine, the pursuit of sustainability may be an illusion, and that in the short-run, at least, external subsidies will remain necessary"--National Bureau of Economic Research web site.