Cognitive Diagnostic Assessment for IELTS Speaking Skills: A Chinese High School Case Study

This qualitative case study investigated how a Cognitive Diagnostic Assessment framework enhanced International English Language Testing System speaking skills among Chinese high school English as a Foreign Language learners. The significance of this research lies in addressing the critical gap between diagnostic assessment theory and practical implementation in examination-oriented educational contexts. The study examined three key questions: how cognitive subskills develop through diagnostic assessment, what feedback processing strategies students employ, and what pedagogical challenges teachers face during implementation. The 16-week intervention at an international school in southwest China involved five Grade 11 students at the Common European Framework of Reference A2 level and one experienced teacher. Data collection included semi-structured interviews, classroom observations, mock test recordings, and document analysis. Findings revealed significant improvements across five subskills: linguistic knowledge, syntactic complexity, pronunciation mastery, discourse management, and speech structure awareness. Students evolved from surface-level feedback engagement to sophisticated metacognitive processing strategies, particularly in pattern recognition and cross-contextual transfer. The teacher’s implementation emphasized culturally sensitive adaptations, addressing face-saving concerns and reconciling diagnostic assessment with examination traditions. The study demonstrates that integrating diagnostic assessment principles with culturally responsive pedagogy enhances speaking development for high-stakes examinations, with implications for curriculum design and teacher education. The single-site nature and small sample size limit generalizability, warranting broader implementation studies across diverse Chinese educational contex