Reinforcing Activity Theory on Least Mastered Topics Using Strategic Intervention Material (SIM) for Grade 8 Students

This action research determined the effectiveness of a teacher-developed Strategic Intervention Material (SIM) in improving the mastery of Grade 8 students on Work, Energy, and Power, the least mastered topic in the first quarter of science based on item analysis. Anchored on Activity Theory, the study compared the academic performance of remediation students taught through the Traditional Method with those who used the SIM. A comparative pre-test–post-test design in purposive sampling was used. A total of 16 students who attended first quarter remediation were included: 8 in the control group (Traditional Method) and 8 in the experimental group (SIM). The small sample size and the all-male composition of the participants are acknowledged as limitations affecting generalizability. The pre-test and post-test were performed as the validated 15-item teacher-made test, analyzed by item analysis by utilizing the difficulty and discrimination indices. Data were analyzed using the Mean Percentage Score (MPS) to describe each group’s pre- and post-test mastery; a paired-samples t-test with Cohen’s d was then computed to test the within-group change in the experimental group. Comparisons between the two groups were made descriptively because individual control-group scores were not available for an independent samples t-test. Results showed that the control group’s mastery increased from 24.38% to 45.00% (a gain of 20.62%), while the experimental group’s mastery increased from 40.00% to 65.00% (a gain of 25.00%). Within the experimental group, the paired-samples t-test yielded t(7) = 11.73, p < .001, with Cohen’s d ≈ 4.15, indicating a statistically significant and very large within-group gain; the null hypothesis was therefore rejected. The findings suggest that the SIM, designed to require minimal teacher supervision, is a promising activity-based tool for re-teaching least-mastered competencies and reinforces Activity Theory in Science instruction. Given the limitations of sample size, sampling method, and gender composition, the results should be interpreted with caution and replicated with larger and more diverse samples before broader claims can be made.