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The COVID-19 Pandemic’s Impact on 9th Grade Students’ Mathematics Achievement

In this research, the influence of the Coronavirus disease (COVID-19) pandemic on 9th grade students’ mathematics achievement is analyzed through quantitative and qualitative methods. A posttest only with control group design was used to compare the mathematics marks of 9th grade students from the previous school year (before the pandemic, control group) and the current school year (during the pandemic, experimental group). Seventy-three students from a public high school in Spain attending class on alternate days participated in the study. Three focus group sessions were held with students, and five semi-structured interviews were conducted—two with teachers and three with students’ families. Results show statistically significant differences in students’ mathematics achievement, with students enrolled in 9th grade the previous (pre-pandemic) year outscoring their peers currently enrolled in 9th grade (during the pandemic) by 22.17%. An overall negative effect size of Hedge’s g = -1.11 was reported. Although significant statistical differences between groups were reported for both male and female students, the effect was 42.31% larger for male students (Hedge’s g = -1.11) than for females (Hedge’s g = -0.78). The qualitative information supported the quantitative results. Changes in educational settings, students’ lack of motivation, monotony, and students’ level of responsibility were qualitatively reported as factors that may explain this phenomenon. The main conclusion of this study is that the COVID-19 pandemic may be significantly and negatively affecting 9th grade students’ mathematics achievement.