An extension of G. L. Cates et al. (2003) investigation was conducted to determine if students' cumulative learning rates would be superior for words read under a traditional drill and practice condition (as they were for spelling in the previous study) than under interspersal conditions of varying ratios of unknown to known words. Participants consisted of three intermediate grade students who were delayed readers. They received a less challenging ratio of unknown to known word (High-P sequencing) interspersal procedure, a more challenging ratio of unknown to known word interspersal training procedure, and a traditional drill and practice procedure in an alternating fashion across several tutoring sessions. Cumulative words read with mastery and cumulative rates of words read with mastery were measured across sessions for each participant under each instructional condition. Findings were consistent with the Cates et al., study revealing that children learn more words per minute of instructional time under the traditional drill and practice condition. These results further support examining instructional efficiency as well as effectiveness when making decisions about selecting and implementing interventions.