There is an urgent need to better understand the role that the use of blended finance in development co-operation can play in achieving the SDGs. By adopting the “Blended Finance Principles for Unlocking Commercial Finance for the SDGs” in 2017, members of the OECD’s Development Assistance...

This paper clarifies the various definitions of additionality currently in use, and explores the relationship between additionality and key evaluation terms, such as impact and causality. It concludes that additionality should be assessed both ex ante and ex post, and that the presence of...