This document discusses challenges and opportunities for improving evaluation of development programs to better account for systemic change. It notes the need for systemic thinking to address new challenges like measuring indirect participation and maintaining accountability with flexibility. Three key evaluation challenges are identified: 1) adopting consistent measures of indirect participation, 2) finding ways to demonstrate accountability under flexible interventions, and 3) adapting causal modeling to evaluate evolving systems and guide practice. The document advocates advancing knowledge of sustainability through meaningful indicators of systemic change beyond intended routes and effects.