The Development Effectiveness Review (DER) is a key component of the Bank’s efforts to be transparent about how we are making a difference in the lives of the people of this Region. Each year, the Review encourages us to reflect on how we are performing and highlights lessons to help us learn from our successes and setbacks during implementation. The trends we identify are used to directly inform improvements in project design, implementation approaches and strategic realignment of priorities. This continuous improvement cycle - where evidence informs intervention design, implementation generates new evidence and learning drives adaptation - should create a feedback loop where results measurement helps to drive and enhance development impact.