For well over a decade, the OECD has developed and published a broad range of comparative indicators that provide insights into the functioning of education systems. These provide crucial information on the functioning, evolution and impact of education, from early childhood through formal education to learning and training throughout life. They provide an opportunity for each country to see its education system in the light of other countries' performances.Fundamental to the credibility and understanding of these comparisons are the concepts, definitions, classifications and methodologies that have been developed to underpin the statistics and indicators. This handbook, for the first time, draws these methodologies together in a single reference volume, providing an invaluable aid to both users and providers of OECD statistics on education.The handbook provides answers to questions such as "What is a teacher?", "What do we mean by public education expenditure?" as well as questions concerning the use of the indicators "How should I interpret expenditure per student? What is it measuring?".In doing so, the handbook aims to facilitate a greater understanding of the OECD statistics and indicators produced and so allow for their more effective use in policy analysis. Equally, it provides a ready reference of international standards and conventions for others to follow in the collection and assimilation of educational data.