1. School of Public Health, Brown University, Providence, RI, USA,
2. Global Health Initiative, Northeastern University, Boston, MA, USA,
3. Health Economics Unit, Mexican Institute of Public Health, Cuernavaca, Mexico,
4. Department of Economics, University of Nairobi, Nairobi, Kenya,
5. School of Public Health, University of California at Berkeley, Berkeley, CA, USA and
6. School of Public Health, University of Nairobi, Nairobi, Kenya