Critics of the No Child Left Behind Act (NCLB) suggest that the effects of state-mandated testing are primarily negative, causing teachers to narrow the curriculum and drill students on tested material. However, the implementation of assessment programs that provide rapid diagnostic information about student progress may allow teachers to prepare students for state-mandated tests while preserving a balanced curriculum. This study investigated teachers' instructional decision-making processes in a Texas school district that implemented an assessment program that provides rapid feedback to teachers regarding student progress throughout the school year. The study suggests how the implementation of rapid assessment systems can foster balanced instruction and positive use of test results, resulting in positive effects of state-mandated testing on teaching and learning. Funding to implement this type of rapid assessment system may improve the probability that the No Child Left Behind Act will have a positive impact on public education.