[1] Inst Salud Publ Chile, Dept Asuntos Cientif, Subdept Estudios & Evaluac Tecnol Sanitarias, Santiago, Chile
[2] Pontificia Univ Catolica Chile, Dept Salud Publ, Fac Med, Santiago, Chile
[3] Univ Desarrollo Clin Alemana, Fac Med, Santiago, Chile
[4] Univ York, Dept Hlth Sci, York YO10 5DD, N Yorkshire, England