States' policy approaches to accountability tend to divide between a primary emphasis on input guarantees and a primary emphasis on performance guarantees. In the midst of keen controversies about the impact of high-stakes testing under the No Child Left Behind Act, this article examines separate and joint effects of input-guarantee versus performance-guarantee policies on reading and math achievement. Combining data from state policy surveys, the School District Finance Survey (F-33), and the Schools and Staffing Survey, the study examines 50 states' activism in test-driven external accountability policies and their support for key school resources (per-pupil spending, class size, in-field teaching). The school resources factor is not correlated with the accountability policy factor at the state level, implying that high-stakes testing pressure was not balanced with school support. Further, hierarchical linear growth models were used to examine interstate variations in the trends of National Assessment of Educational Progress 4th- and 8th grade reading and math scores. The effects of accountability policy alone were not significant in reading and math, whereas the joint effects of accountability and resources were significant in math. The findings suggest that the effects of accountability on academic achievement are moderated by the availability of school resources and that the states can help schools make greater academic progress by combining a performance guarantee approach with an input-guarantee approach.