A vertically integrated experimental–practice curriculum enhances research competency development in research-oriented undergraduate medical education: evidence from a 2021-2025 cohort and performance variability analysis

Background. The Development of research competence is a central goal of undergraduate medical education, particularly in programs oriented toward training future researchers. However, traditional laboratory courses are often fragmented and predominantly verification-oriented, limiting their capacity to foster higher-order research skills. Vertically integrated curricula have been proposed to address this limitation, yet empirical evidence—particularly regarding the role of performance variability in reflecting competency development-remains limited. Methods. This study evaluated a five-year vertically integrated experimental-practice curriculum implemented in a research-oriented basic medical sciences program. Course-based performance data were collected from undergraduate student cohorts between 2021 and 2025. Course characteristics and performance indicators, including mean scores, standard deviation, and score distribution, were analyzed across curriculum levels. Trends in both central tendency and variability were examined to explore their association with curriculum progression. A conceptual model was developed to interpret the relationship between curriculum structure, performance patterns, and research competency development. Results. The curriculum demonstrated a clear progression in learning objectives, instructional strategies, and assessment approaches. Mean scores decreased from 88.75 in foundational courses to 78.25 in advanced courses, whereas standard deviation increased from 4.70 to 8.59, indicating a marked expansion in performance variability. This pattern suggests increasing differentiation in student performance as curriculum complexity intensified within a research-oriented training context. A conceptual model was proposed to illustrate the progressive development of research competencies and to conceptualize performance variability as an indicator of competency differentiation. Conclusions. A vertically integrated experimental–practice curriculum may effectively support the progressive development of research competencies in research-oriented undergraduate medical education. Based on data from cohorts enrolled between 2021 and 2025, the findings suggest that increasing performance variability reflects differentiated learning trajectories rather than reduced educational effectiveness. These results provide both empirical and conceptual support for the design and evaluation of research-oriented curricula in medical education.