The mathematics content domains and underlying topic areas assessed in TIMSS 2019 are documented in the TIMSS 2019 Mathematics Framework, which was developed in collaboration with the participating countries. The mathematics topics included in the TIMSS assessments do not represent the intersection of the topics that are universally taught but rather are a forward-looking conception of mathematics teaching and learning.

Exhibit 12.4 shows the TIMSS mathematics content domains—number, measurement and geometry, and data—and the 17 underlying topics in the TIMSS fourth grade mathematics assessment (see About the Scale). There were 7 topics in number, 7 in measurement and geometry, and 3 in data. Exhibit 12.6 shows the same information for the eighth grade mathematics assessment, with its four content domains—number, algebra, geometry, and data and probability and the 22 underlying topics. There were 3 topics in number, 7 in algebra, 6 in geometry, and 6 in data and probability. Teachers were asked to indicate, for each topic, whether it had been “mostly taught before this year” to students in the assessed class or “mostly taught this year,” or had been “not taught or just introduced” to students. This information serves as an indicator of the “implemented curriculum.” It also can be examined together with information provided by TIMSS National Research Coordinators about whether each of the TIMSS 2019 mathematics topics was included in their countries’ intended curriculum through the fourth or eighth grade and, if so, whether the topics were intended to be taught to “all or almost all students” or “only the more able students.” This information about the intended curriculum is reported in the TIMSS 2019 Encyclopedia.

Exhibit 12.5 presents fourth grade teachers’ reports about the TIMSS mathematics topics that had been taught to students in fourth grade classrooms either prior to or during the year of the assessment. The exhibit shows, for each country and the international average, the percentage of students whose teachers reported that the students had been taught each of the topics (before or during the year), averaged across all topics in each mathematics content domain, and also across all topics in all mathematics domains. Exhibit 12.7 presents parallel information for the eighth grade, reported by teachers about the TIMSS mathematics topics in the eighth grade assessment.

In the fourth grade, according to their teachers, 80 percent of students, on average, had been taught the TIMSS mathematics topics overall. This finding ranged from 97 percent in Azerbaijan and Portugal to 62 percent in Morocco. On average, 86 percent of students had been taught the TIMSS number topics, and 76 percent and 78 percent had been taught the measurement and geometry and data topics, respectively. There was, however, considerable variation from content domain to content domain and from country to country, reflecting differing mathematics curricular emphases.

In the eighth grade, on average, 72 percent of students had been taught the TIMSS mathematics topics overall, according to their teachers. Teachers’ reports about the degree of implementation ranged from 95 percent of students in Malaysia to 49 percent in Finland. Almost all of the students (98%), on average, had been taught the number topics by the end of eighth grade, according to their teachers, with 100 percent of students in a number of countries. The coverage of algebra and geometry was lower, with 68 percent of the students having been taught the algebra topics and 76 percent having been taught the geometry topics, on average. The least instructional attention was given to the topics in data and probability, with 60 percent of students having been taught the topics in this domain, on average. There was considerable variation across countries, particularly in the percentages of students taught the data and probability topics.