Development and Preliminary Validation of CHEM-LENS: A Diagnostic Instrument for Identifying Senior High School Chemistry Learning Needs

Instructional planning in Senior High School chemistry is frequently informed by summative assessment outcomes, which offer limited diagnostic insight into students’ topic-specific learning needs. This study reports the development and preliminary validation of CHEM-LENS (Chemistry Learning Needs Survey), a curriculum-aligned diagnostic instrument designed to identify perceived learning difficulties across major chemistry domains. Employing a quantitative descriptive research design, CHEM-LENS was developed through a staged, theory-informed process encompassing curriculum-based item construction, readability evaluation, expert content validation, pilot testing, item analysis, and estimation of internal consistency reliability. The finalized 50-item instrument was administered to Senior High School students (n = 80), with a separate pilot sample (n = 50). Findings indicated acceptable preliminary measurement quality, including strong expert-rated content validity, satisfactory item functioning, and good internal consistency reliability (Cronbach’s α = .83). Results of the needs assessment revealed differentiated patterns of chemistry learning difficulty, with thermochemistry, chemical reactions, chemical bonding, and atomic structure emerging as high-priority learning need areas. In contrast, topics grounded in foundational concepts and real-life applications were perceived as less challenging. Collectively, these findings suggest that CHEM-LENS demonstrates adequate preliminary quality for diagnostic use and holds promise for supporting data-informed instructional planning in Senior High School chemistry. Further psychometric validation is recommended to strengthen its measurement properties and applicability across diverse educational contexts.