First Author:   Arshia Amiri Department of Agricultural Economics, College of Agriculture, Shiraz University, Shiraz, Iran arshiaamirishiraz@gmail.com         Second Author: Ulf-g Gerdtham Health Economics & Management, Institute of Economic Research, Lund University Ulf.Gerdtham@nek.lu.se         Third Author: Bruno Ventelou Aix Marseille School of Economics (Greqam CNRS & SESSTIM Inserm IRD Université Aix-Marseille) bruno.ventelou@inserm.fr