This article describes a secondary analysis of a brief reading comprehension rate measure, percent comprehension questions correct per minute spent reading (%C/M). This measure includes reading speed (seconds to read) in the denominator and percentage of comprehension questions answered correctly in the numerator. Participants were 22 4th-, 29 5th-, and 37 10th-grade students. Results showed that reading speed accounted for much of the variance in Broad Reading Cluster scores and subtest scores of the Woodcock-Johnson III Tests of Achievement across all grade levels. Converting reading speed to the rate measure %C/M increased Broad Reading Cluster variance accounted for in the 4th- and 5th-grade sample, but decreased the Broad Reading Cluster variance accounted for in the 10th-grade sample. Discussion focuses on the importance of reading speed and the failure to enhance validity of a brief rate measure in more skilled readers by incorporating a direct measure of comprehension. (Contains 5 tables.)