It is essential in any country to have and education system of quality. It is important to build schools in developing countries, but how does one go about ensuring that the schools are providing the necessary education to their pupils? Even in developing countries it is important to track the quality of the education provided, and the best indicator is the achievement levels of the pupils in the system. In this booklet, the author underlines that educational quality is measured principally by outputs rather than inputs. He describes methods of measuring these outputs which have been applied in national and international studies. The booklet explains what it is to monitor educational achievement using examples from international studies and proposes some answers to regularly raised questions. A number of issues facing educational planners are also highlighted. A simple writing style has been adopted so as to benefit a wide audience.