O 3 Ina V. S. Mullis Michael O. Martin, Matthias von Davier, Editors timss 2023 Assessment Frameworks

Cognitive Domains at the Fourth and Eighth Grades
Fourth Grade
Content Domains
Percentages
Life Science
45%
Physical Science
35%
Earth Science
20%
Eighth Grade
Content Domains
Percentages
Biology
35%
Chemistry
20%
Physics
25%
Earth Science
20%

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TIMSS & PIRLS
Lynch School of Education
International Study Center
TIMSS 2023 SCIENCE FRAMEWORK 
21
Cognitive Domains
Percentages
Fourth Grade
Eighth Grade
Knowing
40%
35%
Applying
40%
35%
Reasoning
20%
30%
The content domains differ for the fourth and eighth grades, reflecting the nature and difficulty 
of the science taught at each grade. There is more emphasis at the fourth grade on life science than its 
counterpart, biology, at the eighth grade. At the eighth grade, physics and chemistry are assessed as 
separate content domains and receive more emphasis than at fourth grade, where they are assessed as 
one content domain (physical science). The Earth science content domain has the same level of emphasis 
at both grades, but the objectives at the eighth grade are more sophisticated than at the fourth grade.
The three cognitive domains (knowing, applying, and reasoning) are the same at both grades, 
encompassing the range of cognitive processes involved in learning science concepts, and then applying 
these concepts and reasoning with them.
In 2023, TIMSS Science also will assess key science practices. These practices include skills from 
daily life and school studies that students use in a systematic way to conduct scientific inquiry and 
investigation and that are fundamental to all science disciplines. Increasing emphasis has been placed 
on science practices and science inquiry in many countries’ current science curricula, standards, and 
frameworks.
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Facility with science practices is essential for students to learn and understand science 
concepts and to understand and appreciate the nature of science and scientific knowledge.
The practice of science is, by its very nature, strongly connected to the area of science under study 
and, therefore, cannot be assessed in isolation. Some items in the TIMSS 2023 science assessment at 
both the fourth and eighth grades will assess one or more of these important science practices together 
with content specified in the content domains and thinking processes specified in the cognitive domains. 
The science practices will primarily be assessed through the science PSIs, however. In the PSIs, students 
conduct extended investigations and inquiries in a science content area and in doing so engage in one 
or more of the science practices.
The next two sections of this chapter present the TIMSS 2023 science content domains for fourth 
and eighth grades, followed by a description of the cognitive domains, which are applicable to both 
grades. The chapter concludes with a description of the science practices.
Science Content Domains—Fourth Grade
Three major content domains define the science content for the TIMSS Science fourth grade assessment: 
life science, physical science, and Earth science. Exhibit 2.2 shows the target percentages of testing time 
for each of the three content domains in the TIMSS 2023 Science assessment.

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