When the 2017 National Assessment of Educational Progress was released earlier this year, most states learned that their average scores in grades 4 and 8 reading and mathematics remained relatively flat since 2015. More troubling though, students performing at the lowest 10th and 25th percentiles saw a decline in their scores. To confront this decline, states like Mississippi and Wyoming are focusing their accountability systems on improving the academic growth of their lowest-performing students. This policy update discusses how Mississippi and Wyoming measure academic growth. States like Mississippi and Wyoming provide useful examples of how officials can incorporate growth measures, as well as measures focused on the growth of low performers, in their accountability systems. These states are able to set goals for these students' achievement and track progress toward them.