Governments, NGOs and corporations collaborate across the world on campaigns to respond to global health issues such as AIDS, Ebola, SARS and malaria. But how do you regulate these PPPs (private-public partnerships)? And how do you analyse the accountability, effectiveness and sustainability of the biggest campaigns? Clinton is Vice Chair of the Clinton Foundation and a Lecturer at the Mailman School of Public Health at Columbia. Sridhar is Professor of Global Public Health at the University of Edinburgh. Chaired by the science writer and climatologist Gabrielle Walker.