This study develops and validates a Critical Thinking Disposition (CTD) scale specifically designed for Chinese high school students, addressing the need for assessment tools tailored to this particular demographic. Anchored in Facione's seven-dimensional framework and previous conceptual research, the study employed a rigorous three-phase process-item development, pilot testing, and final validation-using two convenience samples to examine the scale's psychometric properties. Exploratory and confirmatory factor analyses refined the instrument into a five-dimensional structure: Systematic-analyticity, Open-mindedness, Confidence in Reasoning, Reflective Skepticism, and Truth-seeking. The final model demonstrated optimal fit indices (χ²/df = 2.173, CFI = 0.964, RMSEA = 0.043), confirming its structural stability. In addition, convergent and discriminant validity were supported by Average Variance Extracted (AVE), Composite Reliability (CR), and the Fornell-Larcker criterion. At the same time, internal consistency was evidenced by robust Cronbach's α (0.881) and McDonald's ω (0.908) values for the overall scale. Multi-group CFA further established measurement invariance across gender (ΔCFI <0.01, ΔRMSEA <0.015). Overall, the scale provides a reliable and theoretically grounded instrument for assessing CTD in secondary education contexts, enabling educators to evaluate the CTD of high school students comprehensively.

Critical thinking (CT) is widely recognized as a central goal of science education, yet its mechanisms within specific disciplinary contexts remain underexplored. This study developed a biology-specific theoretical model of CT through qualitative analysis of high school students’ engagement with contradictory evidence. Data included pen-and-paper responses from 196 students and eight classroom dialogue transcripts, analyzed using Corbin and Strauss’s coding procedures, with sequential batching and external validation. Selective coding identified questioning—transforming multiple criteria—as the core category, supported by four major categories: evolving evaluative criteria, various types of reasoning, analysis without judgment, and the application of empirical knowledge across criteria. This model explains how learners shift between confirmation, falsification, and reconstruction when anomalies disrupt initial assumptions. To extend its theoretical reach, the model was placed in heuristic dialogue with Kuhn’s structure of scientific revolutions. The comparison highlights the cyclical nature of CT development: anomalies destabilize prevailing frameworks and trigger reorganization of evaluative criteria, fostering cognitive growth. By explicating how students engage with contradictory evidence and transform evaluative criteria, this study elucidates the emergence of critical thinking in disciplinary practice. The findings also inform the design of biology learning environments that deliberately incorporate anomalies and cognitive conflicts, and justify the integration of history and philosophy of science (HPS) perspectives to support students’ questioning, analysis, and criteria revision in authentic scientific contexts.