This paper aims to recognise the transformations in the concept of quality as formulated by Chilean educational policies between 1985 and 1990, at the beginning of the educational privatisation process. Using a conceptual history approach allowed us to analyse the meanings attributed to the concept of quality in the design and implementation of two evaluation systems: The Educational Quality Assessment System (SECE, Spanish initials) and the Educational Quality Measurement System (SIMCE, Spanish initials). The findings show a transformation in meaning for the concept of quality. It moved from the operationalisation, management, and improvement of school systems to equating quality with the results of educational evaluations. This new definition of quality resulted from decisions by the Chilean State, which simplified its complexity and helped manage the new school system. An implication of this semantic transformation is the understanding of quality as a tool used to rank schools.