This study examined the technical adequacy of vocabulary-matching curriculum-based measurement (CBM) to identify and monitor the progress of 148 middle school students in social studies. In addition, the effectiveness of a reading comprehension intervention, Collaborative Strategic Reading (Klingner, Vaughn, Dimino, Schumm, & Bryant, 2001), was examined across 8 weeks with 15 low-achieving middle school readers who were monitored with content-area reading passages. Results indicated vocabulary-matching CBMs are valid and reliable indicators of performance in social studies. Significant differences were found for the intervention group on performance on pre to post vocabulary-matching CBM scores. Difference-in-Differences regression models were used to examine differences between groups on pre-post measures. No significant differences were found between groups in weekly change in scores or trend in performance on vocabulary-matching CBM. (Contains 1 figure and 4 tables.)