The purpose of this study was to compare the cognitive processing profiles of school-age children (ages 7 to 17) who met criteria for underachievement in oral reading accuracy based on three different methods: 1) use of a regression-based IQ-achievement discrepancy only (REGonly), 2) use of a low-achievement cutoff only (LAonly), and 3) use of a dual-discrepancy method requiring children to meet both IQ-achievement and low-achievement criteria (DUAL). Children who were normally achieving (NA) were also included in this study. Thus, four groups of children were compared. For the purposes of this study, a reading accuracy composite was created that included measures of single word reading, nonword reading, and contextual reading accuracy. In order to determine whether there are differences between the children identified as underachieving using these methods, the standardized IQ, reading, and cognitive processing test scores of over three hundred children evaluated at the Northwestern University Speech, Language, and Learning Clinic were reviewed. Cognitive processing tests included measures of processes directly related to reading (i.e., phonological awareness (PA), rapid automatic naming (RAN)), and processes indirectly related to reading (i.e., auditory memory (AM), and visual processing speed (VPS)). Of the four groups, results indicated that children who have a DUAL discrepancy demonstrated below average oral reading accuracy and processing in areas directly related to reading (PA, RAN) that were significantly weaker than their indirectly related processing (AM, VPS). In other words, they demonstrated deficits specifically related to reading while other processes were intact. Their overall processing profiles were also significantly different from the NA children, who demonstrated average range reading and similar direct and indirect processing. The REGonly children also had average range reading but had a processing profile that was similar to the DUAL group. The LAonly children had below average reading and a processing profile that was similar to, but weaker than that of the NA children. These results suggest that the use of a combined low-achievement criterion and a regression-based IQ-achievement discrepancy will identify children whose reading is significantly weaker than NA children and who have cognitive processing weaknesses that are specific to reading. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]