Attention is starting to turn to how the ambitious post-2015 agenda will be financed. High expectations are being set for the role that domestic resource mobilization can play in financing the post - 2015 development goals. Our new NSI Report analyzes recent domestic resource mobilization performance in Africa and estimates a tax effort index for sub - Saharan African countries. Tax mobilization in the region is increasing, but the trend is driven by resource rich countries and resource related taxes. However, mobilization remains low despite significant effort and recent reforms in non-resource rich sub-Saharan countries. This is often the result of a combination of structural factors, inefficient and ineffective tax systems, significant tax exemptions, tax avoidance and capital flight. Expectations regarding the extent to which domestic revenue can finance ambitious post - 2015 goals need to be tempered. Mobilization goals need to be balanced against growth, investment and other objectives. Ultimately enhancin g tax mobilization is about building a better state - citizen compact than exists across most countries in the region today.