Development of A Diagnostic Assessment Instrument For Mathematics Learning For Grade II Elementary School

This study aims to develop a valid diagnostic assessment instrument for second-grade elementary school mathematics (addition and subtraction of whole numbers). Existing diagnostic instruments mostly target other grade levels or focus on misconceptions, while lower-grade teachers still need a ready-to-use instrument that links students’ answers to coding, interpretation, and follow-up actions. This research and development study used a 3D model (Define, Design, Develop) modified from Thiagarajan’s 4D model. The product is a 12-item instrument (5 multiple-choice and 7 short-answer items; maximum score 19) with a test blueprint, answer keys, coding guidelines, interpretation, and follow-up plans. Validation by two expert lecturers and one classroom teacher yielded an average validity of 86.67% (very valid). A small-group trial with five students produced a mean score of 83.16; two students were in the “full understanding” category and three in the “partial understanding” category. The least mastered indicators were addition with regrouping and subtraction with borrowing (two of five students each). The instrument is valid and feasible as a teacher’s tool for mapping students’ initial understanding; its effectiveness and psychometric properties need to be tested with larger samples.