TIMSS assesses students in participating countries in their fourth year of formal schooling, provided the mean age at the time of testing is at least 9.5 years, and in their eighth year of formal schooling, provided the mean age at the time of testing is 13.5 years.

TIMSS 2023 was conducted as a computer-based assessment, transitioning from the previous paper-based format.

TIMSS 2023 was conducted in 64 countries and 8 benchmarking systems.

The TIMSS 2023 framework outlines the assessment objectives and guidelines for the study.

TIMSS 2023 provides achievement data for participating countries, allowing for comparisons and trends analysis.

TIMSS 2023 collects contextual data through questionnaires administered to students, parents, teachers, and schools.

TIMSS assesses students in participating countries in their fourth year of formal schooling, provided the mean age at the time of testing is at least 9.5 years, and in their eighth year of formal schooling, provided the mean age at the time of testing is 13.5 years. Because education systems vary in structure and in policies and practices with regard to age of starting school and promotion and retention, there are differences across countries in how the target grades are labeled and in the average age of students.

Moreover, some countries choose to administer TIMSS to a different grade than the fourth or eighth years of formal schooling. Norway chose to assess fifth and ninth grade students to obtain better comparisons with Sweden and Finland. South Africa and its benchmarking systems assessed fifth and ninth grade students to better match their curricula and to maintain trend measurement. Turkey also chose to assess students in the fifth grade.

In each grade, nationally representative samples of approximately 4,000 students from 150 to 200 schools participated in TIMSS 2023. Including the mathematics and science assessments and context questionnaires, more than 330,000 students, 310,000 parents, 11,000 schools, and 22,000 teachers participated in the fourth grade assessment, and a further 250,000 students from 8,000 schools, and 30,000 teachers participated in the eighth grade assessment.

Appendix B of this report provides information about the grades assessed in each country, including the country’s name of that grade or grades, as well as the mean age of students in each grade assessed in TIMSS 2023.

In each grade, nationally representative samples of approximately 4,000 students from 150 to 200 schools participated in TIMSS 2023.

In each grade, nationally representative samples of approximately 4,000 students from 150 to 200 schools participated in TIMSS 2023.