Education in STEM Entrepreneurship (ESTEME) is a program aimed at developing 21st century skills in undergraduate engineering, science, and business students through entrepreneurship training. The key innovation in ESTEME is that students not only create a novel product and write a business plan, but actually produce and take the product to market. ESTEME is being assessed to identify 1) the entrepreneurial competencies SPIEED students develop, 2) the processes by which these competencies are developed, and 3) any incremental learning that occurs through commercializing an original technology, product, or service. Our goal is to collect systematic data to begin to understand what and how the students learn. We want to provide insights into how engineering and science students develop entrepreneurial behavior and by so doing influence the design of entrepreneurial STEM programs.