Oklahoma teachers and administrators received value-added results in spring 2016, which are based on instruction provided in the 2014–2015 school year. This is the third year in which Oklahoma’s Teacher and Leader Effectiveness Evaluation System (TLE) has provided value-added results to educators. The results are calculated using value-added models, which separate teachers’ contributions to student achievement from other factors. This issue brief provides an overview of the approach that Mathematica applied to produce the value-added results used in the evaluation system. It also describes updates to the value-added models that were used to produce the results distributed in spring 2016.