The No Child Left Behind Act (NCLBA) requires that states improve academic performance so that all students reach proficiency in reading and math by 2014 and that achievement gaps close among student groups. States set annual proficiency targets using an approach known as a status model, which calculates test scores 1 year at a time. Some states have interest in using growth models that measure changes in test scores over time to determine if schools are meeting proficiency targets. To determine the extent that growth models were consistent with NCLBA's goals, GAO assessed (1) the extent that states have used growth models to measure academic achievement, (2) the extent that growth models can measure progress in achieving key NCLBA goals, and (3) the challenges states may face in using growth models to meet adequate yearly progress (AYP) requirements and how the Department of Education (Education) is assisting the states. To obtain this information, we conducted a national survey and site visits to 4 states. While growth models are typically defined as tracking the same students over time, GAO used a definition that also included tracking schools and groups of students. In comments, Education said that this definition could be confusing. GAO used this definition of growth to reflect the variety of approaches states were taking.

Twenty-six states were using growth models, and another 22 were considering or in the process of implementing growth models, as of March 2006. States were using or considering growth models in addition to status models to measure academic performance and for other purposes. Seventeen states were using growth models prior to NCLBA. Most states using growth models measured progress for schools and for student groups, and 7 also measured growth for individual students. States used growth models to target resources for students that need extra help or award teachers bonuses based on their school's performance. Certain growth models can measure progress in achieving key NCLBA goals. If states were allowed to use these models to determine AYP, they might reduce the number of lower-performing schools identified for improvement while allowing states to concentrate federal dollars in the lowest-performing schools. Massachusetts sets growth targets for schools and their student groups and allows them to make AYP if they meet these targets, even if they do not achieve state-wide goals. Some lower-performing schools may meet early growth targets but not improve quickly enough for all students to be proficient by 2014. If these schools make AYP by showing growth, their students may not benefit from improvement actions provided for in the law. States face challenges measuring academic growth--such as creating data and assessment systems to support growth models--that Education's initiatives may help address. The ability of states to use growth models to make AYP determinations depends on the complexity of the model they choose and the extent that their existing data systems meet requirements of their model. Education initiated data grants to support state efforts to track individual test scores over time. Education also started a pilot project for up to 10 states to use growth models that met the department's specific criteria to determine AYP. Education chose North Carolina and Tennessee out of 20 states that applied. With its pilot project, Education may gain valuable information on whether growth models overstate progress or appropriately credit improving schools.