This session describes how a selective, public STEM high school has used the College and Work Readiness Assessment (CWRA) in efforts to model student performance and demonstrate achievement gains in critical thinking, analytical reasoning, problem solving, and written communication. In the context of both diagnostic utility and repeated measures student growth, we will describe results from over 400 students and explain how this new measure of high order thinking skills provides reliable results for advanced students. We will also explore the institutional value of having normed data for value-added measures.