Drugs and vaccines that developing countries need are underinvested in because companies can't be sure there is a market. Guarantee a market commitment in advance so pharma will do R&D. See http://www.vaccineamc.org .
Advance Market Commitments is one of the best examples I've ever seen of smart theory translating into practical policy. Great credit goes to Michael Kremer at Harvard, a number of researchers at the Center for Global Development, and funding from the Gates Foundation and support from the World Bank and WHO.
Yikes. I found myself today explaining Advance Market Commitments to my 10 year old daughter. She did an admirable job feigning interest for her policy-interested father.
Nancy Birdsall of the Center for Global Development is now advocating Advance Market Commitments for things other than vaccines - such as green technologies. http://bit.ly/9S1zdt