In light of the achievement gap that widened during the pandemic, this study aimed to develop a diagnostic assessment for teachers to identify students at risk of underachievement. Based on the national curriculum and assessment criteria as a framework, attributes composing achievement criteria were identified and micro-level learning progressions were established about three core ideas in physical science. Through iterative reviews, 116 items were developed and administered, resulting in 355 responses from primary and lower secondary school students. Student responses to most of the items were consistent with the levels of assessment criteria, showing a micro-level learning progression. A few inconsistencies provided insight into modifying learning progressions to align with students' thinking patterns. They also showed learning challenges that require extra support for student learning. Implications for teacher professional development and further research topics are suggested.