Teacher Work Samples (TWS) can be viewed in terms of a product and a process. As a product, the TWS measures a teacher candidate's (TC's) ability to promote student achievement, documents that TCs have met minimum national standards, and validates teacher education programs. Teacher candidates engage in observable, job-related behaviors that serve as predictors of criterion performance. As it leads to a product that measures a TC's ability to promote student achievement, the process of using TWS broadens and deepens the thinking of TCs. This article describes both the process and the product of TWS methodology as used at the University of Northern Colorado.