1. Department of Medical Statistics London School of Hygiene & Tropical Medicine London UK
2. MRC Clinical Trials Unit, UCL London UK
3. TAZAMA Project National Institute for Medical Research Mwanza Tanzania
4. Department of Population Health London School of Hygiene & Tropical Medicine London UK
5. MRC International Statistics and Epidemiology Group London School of Hygiene & Tropical Medicine London UK
6. Africa Health Research Institute Natal South Africa
7. Department of Epidemiology and Biostatistics, School of Public Health Makerere University Kampala Uganda
8. Department of Epidemiology and Biostatistics, School of Public Health University of Zambia Lusaka Zambia
9. School of Public Health University of the Witwatersrand Johannesburg South Africa