<![CDATA[Pembelajaran kolaboratif diperlukan dalam penerapan Contextual Teaching and Learning (CTL) untuk mengonstruksi pemahaman konsep melalui investigasi dan diskusi serta menumbuhkan self-efficacy siswa. Penelitian ini bertujuan untuk meningkatkan kemampuan pemahaman konsep matematis dan self-efficacy melalui penerapan pendekatan Contextual Teaching and Learning (CTL) model Group Investigation (GI) pada materi Teorema Pythagoras. Penelitian dilakukan dengan metode kuantitatif jenis pre-experimental dengan desain one-group pretest-postest. Tahapannya meliputi: (1) pretest, (2) penerapan pendekatan pembelajaran, (3) postest, (4) menganalisis dan menarik kesimpulan. Penelitian dilaksanakan di kelas VII SMP pada salah satu sekolah yang berada di Yogyakarta. Penelitian ini melibatkan satu kelas dengan total 32 orang siswa yang ditentukan menggunakan purposive sampling. Instrumen yang digunakan dalam penelitian terdiri dari tes untuk mengukur pemahaman konsep matematis dan angket untuk mengukur self-efficacy siswa. Uji Wilcoxon Signed Rank menunjukkan hasil signifikan dengan diperoleh p-value < 0,05. Kemampuan pemahaman konsep matematis meningkat dengan nilai (N-gain=0,22), sedangkan self-efficacy siswa meningkat dengan nilai (N-gain=0,07). Nilai effect size pemahaman konsep matematis sebesar 0,7 dan self-efficacy sebesar 0,37. Meskipun diperoleh peningkatan rendah, temuan ini menunjukkan bahwa pendekatan CTL model GI memberikan dampak positif terhadap peningkatan pemahaman konsep matematis dan self-efficacy siswa dalam pembelajaran matematika. Implikasi penelitian ini menunjukkan bahwa pendekatan CTL model GI dapat digunakan sebagai alternatif inovasi pembelajaran untuk mengaitkan konsep matematika dengan konteks kehidupan nyata untuk meningkatkan pemahaman konsep matematis dan self-efficacy siswa. Collaborative learning is essential in the implementation of Contextual Teaching and Learning (CTL) to facilitate students' conceptual understanding through investigation and discussion while fostering their self-efficacy. This study aimed to improve students' mathematical conceptual understanding and self-efficacy through the implementation of the Contextual Teaching and Learning (CTL) approach integrated with the Group Investigation (GI) model on the topic of the Pythagorean Theorem. This study employed a quantitative pre-experimental method using a one-group pretest-posttest design. The research procedure consisted of four stages: (1) pretest, (2) implementation of the instructional approach, (3) posttest, and (4) data analysis and conclusion. The study was conducted in a seventh-grade class at a junior high school in Yogyakarta, Indonesia. The participants consisted of 32 students selected through purposive sampling. The research instruments included a mathematical conceptual understanding test and a self-efficacy questionnaire. The Wilcoxon Signed-Rank Test indicated statistically significant differences (p < 0.05). Students' mathematical conceptual understanding improved with an N-gain of 0.22 and a large effect size of 0.70, while self-efficacy improved with an N-gain of 0.07 and a medium effect size of 0.37. Although the N-gain values were categorized as low, the findings indicate that the CTL approach integrated with the GI model had a positive impact on improving students' mathematical conceptual understanding and self-efficacy. These findings suggest that CTL integrated with the GI model can serve as an alternative instructional approach that connects mathematical concepts with real-life contexts while promoting students' conceptual understanding and self-efficacy in mathematics learning.]]>
