Given math's importance, states are adopting a range of K12 policies to improve math outcomes. As these and other policies unfold, policymakers need to monitor intended outcomes and ultimately gauge impact. They need answers to basic questions: Are more students taking and passing algebra and advanced math? Are performance gaps changing between student groups or schools? What are the characteristics of our math teachers? Are they changing? How are math teachers with different characteristics distributed across schools and students? Policymakers also need answers to more complex questions: Did a given policy have an effect? If so, why, under what conditions, and for whom? Were there any unintended consequences? With these kinds of questions in mind, this CALDER brief singles out the value of longitudinal, individual-level state administrative data by reviewing questions that can--and can't--be answered by the more limited data made publicly available by states. To illustrate, we focus on three states that are attempting to improve math outcomes and that enroll large numbers of students from historically marginalized student groups: California, Florida, and Texas.