Integrating the CER Framework in Argumentative Writing to Foster Logical Thinking and Evidence-Based Reasoning

This study investigates integrating the Claim, Evidence, and Reasoning (CER) framework to enhance students' argumentative writing skills, a critical competency in 21st-century literacy, and employing a mixed-method approach that combines a qualitative descriptive analysis with a pre-experimental design. Data were rigorously collected through semi-structured interviews, direct field observations, and comprehensive writing assessments, including pretest and posttest evaluations. This study employed a mixed-methods approach with a pre-experimental one-group pretest-posttest design involving 30 eleventh-grade students at MAS Al Khairiyah in Jambi, for a total of 412 students, selected through purposive sampling. Quantitative data from performance tests and qualitative data from observations and interviews were analyzed simultaneously using the N-Gain test and an interactive analysis model to describe students' cognitive transformation in argumentative writing. The findings reveal a significant improvement in all argumentative components, with a "highly effective" N-Gain score of 0.86. Students demonstrated a qualitative transition from subjective opinions to structured discourse by mastering clear claims, integrating factual evidence, and engaging in coherent, logical reasoning. This study confirms that the CER framework serves as a robust cognitive scaffold, making it a recommended instructional strategy for developing intellectual rigor and persuasive communication skills.