To overcome the problem of insufficient research and development (R&D) on vaccines for diseases concentrated in low-income countries, sponsors could commit to purchase viable vaccines if and when they are developed. One or more sponsors would commit to a minimum price that would be paid per...

We show that the effect of eviction threats on unobservable investment effort can be positive. We demonstrate this apparently counter-intuitive result in a model of tenancy where investment by a tenant in the current period raises the chances of doing well in the next period, and therefore...