Phase III clinical trials are expensive, require enrolling and treating hundreds or thousands of patients at many sites. The time and cost required to do so is uncertain as is the economic value of the drug upon completion. We consider the problem of determining when and how many test sites...

The Challenge: A Transnational Response to HIV/AIDS -- Profiling the Provision Status of Health-Promoting Public Goods Against AIDS -- International Transfers -- Regional Constraints and HIV/AIDS -- Summary and Concluding Remarks

We examine the role of spillover learning in shaping the value of exploratory versus incremental R&D. Using data from drug development, we show that novel drug candidates generate more knowledge spillovers than incremental ones. Despite being less likely to reach regulatory approval, they are...