COMPASS is an assessment test based on the cognitive model of mathematical problem solving. This test diagnoses components of mathematical ability which are required in the process of understanding and solving mathematical problems. The tasks were selected through the case studies of cognitive counseling, in which researchers individually interview and teach learners who feel difficulty in particular learning behavior. The purpose of COMPASS is to provide diagnostic information for improving learning process and methods of class lessons. Features of COMPASS include: The time limitations are set for each task to measure the target component accurately; questionnaires are incorporated to diagnose orientation toward learning behavior. The present paper aims to introduce the concept and the tasks of COMPASS to show how cognitive science contributes to school education through the development of assessment tests.