Book excerpt: Extension and advisory services (EAS) play a key role in facilitating innovation for sustainable agricultural development. To strengthen this role, appropriate investment and conducive policies are needed in EAS, guided by evidence. It is therefore essential to examine EAS characteristics and performance in the context of modern, pluralistic and increasingly digital EAS systems. In response to this need, the Food and Agriculture Organization of the United Nations (FAO) has developed guidelines and instruments for the systematic assessment of national EAS systems. The Indicator Framework provides overarching guidance on EAS systems assessment, including a list of 40 indicators (10 core and 30 complementary) which cover all major aspects of EAS from inputs to impact. This Indicator Framework provides much needed structure to EAS assessment, taking into account contemporary, pluralistic services and is complemented by FAO’s instruments for participatory data collection in EAS, including quantitative and qualitative data.