Abstract
<title>Abstract</title> <p>This study examined the effectiveness of integrating collaborative learning with Polya’s problem-solving approach in enhancing pre-service teachers’ critical thinking skills in mathematics, with attitudes and engagement as mediators and prior knowledge as a moderator. Guided by a pragmatist paradigm, the study employed mixed-methods quasi-experimental design. A purposive sample of 390 pre-service mathematics teachers participated in the quantitative phase, while qualitative data were obtained from a subset of participants. Quantitative data were collected using a critical thinking achievement test from simultaneous equation and structured questionnaires, and analyzed using PROCESS Macro Model 4 to test mediation and moderation effects. Qualitative data were gathered through open-ended responses and classroom-based evidence and analyzed thematically following Braun and Clarke’s six-phase approach. The results revealed that the integrated instructional approach significantly improved pre-service teachers’ critical thinking skills. Attitudes and engagement were found to play significant mediating roles, while prior knowledge significantly moderated the effectiveness of the intervention. Qualitative findings supported the quantitative results, showing that collaborative engagement, positive attitudes, and sustained participation contributed to higher-order thinking. This study contributes to the literature by integrating collaborative learning with Polya’s problem-solving approach within a single instructional framework and empirically testing both mediating and moderating mechanisms.</p>