The use of oral reading fluency (ORF) passages within a Response to Intervention (RTI) framework is examined. Significant limitations within the current ORF research are discussed. The passage equivalency and readability scores for DIBELS Next, AIMSweb, and a school district's curriculum's ORF passages are evaluated using Generalizability Theory and readability formulas. Multiple regression is used to analyze the contribution of ORF progress monitoring passages for predicting the California Standards Test (CST). The optimal number of ORF passages to administer is also examined. Participants consisted of third and fifth grade students from an urban school district in Southern California. Results indicate that readability formulas provide wide range of scores for individual passages but rank sets of passages fairly equally. Results also indicate that ORF passages have high levels of reliability and variance attributable to student skill. Finally, results also indicate that the addition of progress monitoring did not increase the predictive validity of the CSTs. The implications, limitations, and future direction of research are discussed.