The "PISA 2012 Technical Report" describes the methodology underlying the PISA 2012 survey, which tested 15-year-olds' competencies in mathematics, reading and science and, in some countries, problem solving and financial literacy. It examines the design and implementation of the project at a level of detail that allows researchers to understand and replicate the resulting data and analyses. The reader will find a wealth of information on the test and sample design, modes of delivery (paper-based or computer-based), methodologies used to analyse the data, technical features of the project, and quality control mechanisms. Annexes include: (1) Main Survey Item Pool Classification; (2) Contrast Coding Used in Conditioning; (3) Standard Errors of Means, Sample Sizes, School Variance Estimates, and Other Sampling Outcomes; (4) Mapping of ISCED [International Standard Classification of Education] to Years; (5) National Household Possession Items; (6) Technical Standards for PISA 2012; and (7) PISA Consortium, Staff and Consultants. (Individual chapters contain references.)