This study analyzed the relationship between benchmark scores from two curriculum-based measurement probes in mathematics (M-CBM) and student performance on a state-mandated high-stakes test. Participants were 298 students enrolled in grades 7 and 8 in a rural southeastern school. Specifically, we calculated the criterion-related and predictive validity of benchmark scores from CBM probes measuring math computation and math reasoning skills. Results of this study suggest that math reasoning probes have strong concurrent and predictive validity. The study also provides evidence that calculation skills, while important, do not have strong predictive strength at the secondary level when a state math assessment is the criterion. When reading comprehension skill is taken into account, math reasoning scores explained the greatest amount of variance in the criterion measure. Computation scores explained less than 5% of the variance in the high-stakes test, suggesting that it may have limitations as a universal screening measure for secondary students.