As part of a Response to Intervention (RTI) model, curriculum-based measurement (CBM) is an evidence-based assessment system that uses screening and formative assessments to help guide instruction. The two primary purposes of this study are to examine the relations between the easyCBM benchmark measures and a statewide large-scale assessment and to establish the optimal cut scores for the CBM measures. The easyCBM benchmark measures are used in 13 states through an online assessment system designed for use in an RTI context. Utility of the assessment system is examined through evidence related to predictive and systemic validity evidence. Included are a regression and a receiver operating characteristics (ROC) analysis of the relation between the benchmark assessments and a statewide large-scale reading test using a sample of approximately 3,600 students in grades 4 and 5. Results indicate strong concurrent validity and show the vocabulary measure as a robust predictor across grades. (Contains 3 tables.)