Curriculum-based measurement of oral reading fluency (CBM-R) is widely used across the country as a quick measure of reading proficiency that also serves as a good predictor of comprehension and overall reading achievement, but has several practical and technical inadequacies, including a large standard error of measurement (SEM). Reducing the SEM of CBM-R scores has positive implications for educators using these measures to screen or monitor student growth. The purpose of this study was to compare the SEM of traditional CBM-R words correct per minute (WCPM) fluency scores and the conditional SEM (CSEM) of model-based WCPM estimates, particularly for students with or at risk of poor reading outcomes. We found: (1) the average CSEM for the model-based WCPM estimates was substantially smaller than the reported SEMs of traditional CBM-R systems, especially for scores at/below the 25th percentile; and (2) a large proportion (84%) of sample scores, and an even larger proportion of scores at/below the 25th percentile (about 99%) had a smaller CSEM than the reported SEMs of traditional CBM-R systems. [This is the online first version of an article published in "Assessment for Effective Intervention."]