Jos Vaessen (Ph.D. Maastricht University) is Principal Evaluation Specialist at the Internal Oversight Service of UNESCO in Paris and lecturer at Maastricht University, The Netherlands. After completing his M.Sc. in 1997 (Wageningen University) and prior to starting his current position at UNESCO in 2011, he has been involved in research, teaching and evaluation activities in the field of international development at Antwerp University and, more recently, Maastricht University. Over the last fifteen years or so, he has worked for several multilateral and bilateral international organizations m...