This research evaluates the impact of implementing the CIRC (Cooperative Integrated Reading and Composition) teaching model with the PL (Literacy Improvement) research method on students' understanding in Indonesian language subjects in grade 4 elementary school. Prior to the implementation of the CIRC model, students demonstrated a limited level of understanding of the concepts of fact and opinion, often experiencing confusion in distinguishing between the two. Student participation in the learning process is also relatively low. The results of this study reveal significant changes after implementing the CIRC teaching model. Students experienced a marked increase in understanding of fact and opinion material. They are better able to distinguish between fact and opinion, and have a better ability to identify examples of both. The CIRC model also increases the level of student participation in the learning process, which is reflected in active involvement in group discussions. The OT research method uses literacy metrics that reveal significant improvements in the skills of reading, comprehending, and analyzing texts based on facts and opinions. The conclusion of this research is that the application of the CIRC teaching model has a significant positive impact on students' understanding of Indonesian language subjects, especially in understanding the concepts of facts and opinions. The increase in literacy achieved by students after implementing this model provides strong evidence of its effectiveness. Apart from helping students understand concepts, the CIRC model is also successful in improving students' critical skills in reading and understanding texts. These results provide a strong foundation for continued development and implementation of similar teaching models in other subjects, underscoring the importance of literacy-based approaches to improving student understanding.