This paper reports a feasibility study on developing computer model-based assessments of chemical reasoning at the high school level. Computer models are flash and NetLogo environments to make simultaneously available three domains in chemistry: macroscopic, submicroscopic, and symbolic. Students interact with computer models to answer assessment questions. Student responses provide an indication of student understanding of two big ideas in chemistry: matter-energy and models. Teachers incorporate computer models during chemistry units of instruction and give the computer model-based assessments at the end of unit instruction. Multi-dimensional Rasch modeling was applied to student responses to the assessment items. Results suggest that most assessment items have good technical quality and most assessments have adequate construct validity and reliability. Results also indicate specific areas of improvement for computer models, computer model-based assessments, and integration of the models and assessments in high school chemistry courses. We conclude that computer model-based assessment of learning progression is feasible and promising. (Contains 4 tables and 4 figures.)