This RETA project will develop and evaluate longitudinal models that examine what and how students learn in the school setting. With a focus on mathematics, it draws on a unique data set gathered by the existing Promoting Rigorous Outcomes in Mathematics/Science Education (PROM/SE) project. This Comprehensive NSF/Math and Science Partnership (MSP) effort involving over 300,000 students in grades 3 through 12 and approximately 4,000 teachers in over 50 districts from the states of Michigan and Ohio collected data over the past 4 years, 2004-2008. It consists of multi-grade curriculum measurements at different time points of (a) student knowledge in multiple content topics and of (b) student's opportunity to learn those topics. The sample of students mirrors that of the nation both in demographics and socio-economic factors.