6The Consumer Price Index Manual contains comprehensive information and explanations on compiling a consumer price index (CPI). The Manual provides an overview of the methods and practices national statistical offices (NSOs) should consider when making decisions on how to deal with the various problems in the compilation of a CPI. The Manual draws upon a wide range of experience and expertise to describe practical and suitable methods to guide countries in their efforts to improve the quality and international comparability of their Consumer Price Indices and to meet user needs. It was endorsed by the 51st Session of the United Nationsl Statistical Commission as an official statistical standard on March 4, 2020. Since the publication of the 2004 Consumer Price Index Manual, methods and best practices have evolved. THe updated CPI Manual includes more practical compilation advice for compilers. The new edition also covers relevant developments in methods and practices as well as theory and research over the last decade; updates material on data sources, data collection methods, and related calculation methods to reflect development since 2004; reflects recent developments in user needs; and harmonizes the CPI concepts in line with the 2008 System of National Accounts.