The Annual Status of Education Report (ASER) is a national citizen-led rapid assessment of children's ability to read simple text and do basic arithmetic. ASER is designed and facilitated by the Indian nongovernment organisation Pratham, and has been conducted every year since 2005 by partner organisations in every rural district of India, reaching more than 600,000 children annually. The assessment differs from most other international and national large-scale assessments in several key respects, such as the use of household rather than school-based sampling and the focus on simple tools and indicators that are easy to administer and understand. All ASER metrics, measures and processes are intended to engage ordinary citizens in thinking about and acting to improve basic learning outcomes in India. By conducting a massive national survey each year, ASER has demonstrated that it is possible to use simple, reliable and scientific methods of sampling and assessment on a large scale for high impact at a very low cost. Key to this aspect of ASER has been its ability to mobilise over 25,000 volunteers each year. ASER has been responsible to a large extent for putting the issue of learning on the agenda in India. More recently, the model has been adapted for use in several African and Asian countries. Taken together, these initiatives reached more than a million children in 2012.