The Millennium Development Goals call for reducing by half the proportion of people without sustainable access to safe drinking water. This goal was adopted in large part because clean water was seen as critical to fighting diarrheal disease, which kills 2 million children annually. There is...

Several programs have been proposed to improve incentives for research on vaccines for malaria, tuberculosis, and HIV, and to help increase accessibility of vaccines once they are developed. For these programs to spur research, potential vaccine developers must believe that the sponsor will not...

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...

In 1839, the French government purchased the patent on the Daguerreotype process and" placed it in the public domain. This paper examines a mechanism under which governments" would use an auction to estimate the private value of patents and then offer to buy out patents at" this private value,...

Social commentators from William Julius Wilson to Charles Murray have argued that increased sorting of people into internally homogeneous" neighborhoods,schools, and marriages is spurring long-run inequality. Cali- bration of a formal model suggests that these fears are misplaced. In order to...

Increased HIV risk creates incentives for people with low sexual activity to reduce their activity, but may make high-activity people fatalistic, leading them to reduce their activity only slightly, or actually increase it. If high-activity people reduce their activity by a smaller proportion...

Under asymmetric information about sexual history, sexual activity creates externalities. Abstinence by those with few partners perversely increases the average probability of HIV infection in the pool of available partners. Since this increases prevalence among the high activity people who...

This study reports the findings from a year-long randomized evaluation assessing the impact of assigning 62 classrooms in Nigeria to receive either blocked or interleaved math problem sets. Blocked practice sessions focused on a single skill at a time. Interleaved problem sets alternated between...

We report results from a randomized evaluation of a merit scholarship program for adolescent girls in Kenya. Girls who scored well on academic exams had their school fees paid and received a cash grant for school supplies. Girls eligible for the scholarship showed significant gains in academic...

Colombia's PACES program provided over 125,000 poor children with vouchers that covered half the cost of private secondary school. The vouchers were renewable annually conditional on adequate academic progress. Since many vouchers were assigned by lottery, program effects can reliably be...