UNDP has set up an M&E Sandbox to nurture and learn from new ways of doing monitoring and evaluation (M&E) that are coherent with the complex nature of the challenges facing the world today. In the Sandbox we prioritize action and practical insights ‘from the front lines’ about how to do it, rather than abstract theory and general principles (though those are important too!). In this connection, we seek to explore how M&E needs to be different when we work on complex problems in uncertain and rapidly changing contexts, rather than through the more ‘linear’, control-focused, and projectized M&E that tends to dominate today. By Søren Vester Haldrup with support from Samuel Tran.