Learning by Evaluating (LbE) is an instructional approach that involves students making comparative judgements of pairs of artifacts, such as student work, portfolios, prototypes, or curated images related to a topic of instruction to enhance critical thinking and decision-making skills. Situated as a primer for learning, the efficacy of LbE stems from actively engaging students in the evaluation process, scaffolding their learning, fostering self-reflection in decision-making, and facilitating the transfer of acquired skills and concepts to academic contexts and project work. However, there is an opportunity to gain deeper insights into classroom integration of LbE and the factors that may influence the student experience. This study adopts a design-based research approach to analyze LbE within a secondary STEM education setting, with the objective of optimizing classroom integration. By analyzing student comments generated during LbE, the research explores factors shaping the students' learning experiences, examining the extent to which students engage in informed decision-making, offer justifications, and express sentiments throughout the process. Additionally, the study explores how teachers strategically incorporate LbE into their classroom, aligning LbE sessions with curriculum objectives. Findings indicate a diverse pattern of student engagement, sentiments, and decision-making approaches across STEM classrooms. This study contributes to research on LbE by offering insights into the dynamics between teacher implementation and student engagement. The insights gained highlight the potential for refining the effectiveness of LbE within the classroom. Notably, the research emphasizes the significance of how LbE sessions are framed and strategically integrated to enrich the overall educational experience for both students and educators.