In response to its general mandate to strengthen the volume and developmental effectiveness of aid, the DAC has drawn up a series of policy principles addressing key areas of aid programming and management including Project Appraisal, Programme Assistance and Technical Co-operation. Aid evaluation plays an essential role in the efforts to enhance the quality of development co-operation. The following set of principles state the views of DAC Members on the most important requirements of the evaluation process based on current policies and practices as well as donor agency experiences with evaluation and feedback of results.