The SERNA Conceptual Standard for Inclusive Education and Universal Design for Learning: Definitions, Relationships, and Theoretical Integration (SCS-IEU)

**Background:** Inclusive education, the practice of educating all students regardless of their physical, cognitive, or socio-economic differences in a common learning environment, is a global educational priority. However, the field is characterized by "terminological chaos," where "inclusion," "integration," "accommodation," and "Universal Design for Learning (UDL)" are often used inconsistently or incorrectly. **Problem:** This conceptual fragmentation prevents the development of standardized metrics for "inclusive quality" and limits the ability to compare the effectiveness of different teacher training programs. Specifically, the distinction between "post-hoc accommodation" and "proactive design" remains poorly understood by practitioners. **Objective:** To establish the SERNA Conceptual Standard (SCS-IEU), providing canonical definitions and a testable socio-pedagogical model for inclusive education. **Approach:** A systematic review of over 420 peer-reviewed articles was conducted, synthesizing evidence from special education, instructional design, and educational psychology. **Contributions:** This standard defines 12 canonical terms, establishes the "Proactive Inclusion & Engagement (PIE) Model," and proposes 10 falsifiable hypotheses for future research. **Conclusions:** SCS-IEU provides the theoretical infrastructure to transition inclusion research from descriptive "place-based" advocacy to predictive modeling of student belonging and achievement.