Extent to which an activity or a program can be evaluated in a reliable and credible fashion.
(Organisation for Economic Co-operation and Development (OECD) Development Assistance Committee Working Party on Aid Evaluation. 2002. "Glossary of Key Terms in Evaluation and Results Based Management." Paris: OECD Publications, p. 21. http://www.oecd.org/dataoecd/29/21/2754804.pdf.)