The Trends in International Mathematics and Science Study (TIMSS) is an assessment of the mathematics and science knowledge of fourth (or fifth) and eighth (or ninth) grade learners around the world. TIMSS is designed to allow participating nations to monitor their educational achievements and how their achievements change over time, as well as to compare achievement across borders in the key subjects of mathematics and science. In addition to achievement data, TIMSS collects contextual information about the home, school and classroom to explain learner achievement.