A growth model measures the amount of students' academic progress between two points in time.  This guide is intended to help you decide which growth model, if any, should be used in your State or district. Although growth models are explained models within the framework of NCLB, they can be used for a variety of educational purposes Ã??Ã?¢? not just for high-stakes accountability as is illustrated throughout this guide.  This resource is organized as follows: (a) Why are policymakers talking about growth models?; (b) What are the different types of growth models?; (c) What is needed to implement a growth model?; (d) What are the limitations of growth models?; and (e) How can ...