Principal climate-related aid estimated at USD 12.8 bn on average per year over 2010 to 2011, with total climate-related aid, including principal and significant activities estimated at USD 21.1 bn on average over 2010 to 2011, based on reported donor commitments to the OECD DAC. The framing of the effectiveness issue has changed over time, primarily reflecting changes in the international community’s provisions on aid effectiveness. For example, the Board’s assessment of proposals is to take national strategies and co-benefits into account. A greater emphasis is also placed on monitoring and evaluation (AF, 201 la), drawing on DAC guidance.