The IEA's Trends in International Mathematics and Science Study (TIMSS) is a series of international assessments of the mathematics and science knowledge of students around the world. The participating students come from a diverse set of educational systems (countries or regional jurisdictions of countries) in terms of economic development, geographical location, and population size. In each of the participating educational systems, a minimum of 4,500 to 5,000 students is evaluated. Contextual data about the conditions in which participating students learn mathematics and science are collected from the students and their teachers, their principals, and their parents via questionnaires.
TIMSS is one of the studies established by the International Association for the Evaluation of Educational Achievement (IEA) aimed at allowing educational systems worldwide to compare students' educational achievement and learn from the experiences of others in designing effective education policy. This assessment was first conducted in 1995, and has been administered every four years thereafter. Therefore, some of the participating educational systems have trend data across assessments from 1995 to 2015. TIMSS assesses 4th and 8th grade students, while TIMSS Advanced assesses students in the final year of secondary school in advanced mathematics and physics.
TIMSS was first administered in 1995 as the largest international student assessment study of its time and evaluated students in five grades. In the second cycle (1999) only eighth-grade students were tested. In the next cycles (2003, 2007, 2011 and 2015) both 4th and 8th grade students were assessed. The 2011 cycle was performed in the same year as the IEA's Progress in International Reading Literacy Study (PIRLS), offering a comprehensive assessment of mathematics, science and reading for the countries participating in both studies. The sixth cycle was conducted in 2015, and the results were released in 2016; the data set was published in February 2017. TIMSS 2015 included data collected from parents for the first time. TIMSS Advanced, previously conducted in 1995 and 2008, was also conducted in 2015, and assessed final-year secondary students' achievement in advanced mathematics and physics. Policy-relevant data about curriculum emphasis, technology use, and teacher preparation and training accompanies the TIMSS Advanced results.
Along with the overall students’ achievement data, TIMSS comprehensive assessments include data on student performance in various mathematics and science domains (algebra, geometry, biology, chemistry, etc.) and on performance in the problem solving challenges in each of these contexts. In addition, TIMSS provides contextual data on crucial curricular, instructional, and resource-related factors that can impact the teaching and learning process. These data are gathered using student, teacher, school, and curriculum (national) questionnaires filled out by students, teachers, school principals and National Research Coordinators, respectively.