We argue that in pharmaceutical markets, variation in the arrival time of consumer heterogeneity creates differences between a producer's ability to extract consumer surplus with preventives and treatments, potentially distorting R&D decisions. If consumers vary only in disease risk, revenue...

We discuss how evidence and theory can be combined to provide insight on the appropriate subsidy level for health products, focusing on the specific case of deworming. Although intestinal worm infections can be treated using safe, low-cost drugs, some have challenged the view that mass...

To the extent that students benefit from high-achieving peers, tracking will help strong students and hurt weak ones. However, all students may benefit if tracking allows teachers to present material at a more appropriate level. Lower-achieving pupils are particularly likely to benefit from...

Quah's [1993a] transition matrix analysis of world income distribution based on annual data suggests an ergodic distribution with twin peaks at the rich and poor end of the distribution. Since the ergodic distribution is a highly non-linear function of the underlying transition matrix estimated...

This paper compares retrospective and prospective analyses of the effect of flip charts on test scores in rural Kenyan schools. Retrospective estimates that focus on subjects for which flip charts are used suggest that flip charts raise test scores by up to 20 percent of a standard deviation....

Malaria, tuberculosis, and the strains of HIV common in Africa kill approximately 5 million people each year. Yet research on vaccines for these diseases remains minimal largely because potential vaccine developers fear that they would not be able to sell enough vaccine at a sufficient price to...

While many developing-country policymakers see heavy fertilizer subsidies as critical to raising agricultural productivity, most economists see them as distortionary, regressive, environmentally unsound, and argue that they result in politicized, inefficient distribution of fertilizer supply. We...

We construct and calibrate a model of the world economy in which countries' opportunities to develop depend on their trade with advanced economies. Trade opportunities in turn depend on the relative population of the advanced and developing world. As developing countries become advanced, they...

It is often argued that low tax rates on owner-occupied housing divert investment from equipment. This paper demonstrates that if people are heterogeneous in their propensity to save, and if there are constraints on borrowing, favorable tax treatment of owner-occupied housing up to a certain...

This paper argues that worker cooperatives are prone to redistribution among members, and that this redistribution distorts incentives. I assume that employment contracts are incomplete. In the model cooperative members pay in a capital contribution to purchase equipment. They then receive...