Abstract:
The study analyzed differences in 8th grade students' performance on mathematics portion of TIMSS test through the lens of teacher knowledge. The sample of this study consisted of lower secondary math-ematics teachers from US (grades 6-9, N=102) and Russia (grades 5-9, N=97). The instrument was de-signed to assess teacher content knowledge based on cognitive domains of knowing, applying, and reasoning, as well as addressing lower secondary mathematics topics of Number, Algebra, Geometry, Data and Chance. The study main results suggest that student performance on international tests could be explained by teacher knowledge as well as inform the field on priorities placed on lower secondary mathematics teachers' knowledge in USA and Russia by content and cognitive domains.