The No Child Left Behind Act requires all students be proficient in reading and mathematics by 2014, and students in subgroups to make Adequate Yearly Progress. One of these groups is students with disabilities, who continue to score well below their general education peers. This quantitative study identified scoring differences between disability groups on the Florida Comprehensive Assessment Test (FCAT) over a 6-year period. The percentages of students who scored at the proficient level in reading, mathematics, and writing in the fourth grade, and reading, mathematics, and science in the fifth grade were used to identify differences in 12 disability groups. All students with disabilities are combined into one category for reporting purposes and assigning school grades. Disaggregation of the special education categories revealed scoring differences between groups in all subjects and both grades. Students with speech impairments had the highest number of students scoring at the proficient level in all subjects, while students with intellectual disabilities had the fewest. The categorical rank order was identical for reading in both grades and similar in the other subjects. Students with specific learning disabilities, who constitute approximately 50% of all students with disabilities in these grades, were in the lowest five categories for both grades in reading and in fourth grade mathematics, and in the lower 50% in fifth grade mathematics and science. Recommendations included the need for alternate measures of student achievement; specifically, modified assessments, in addition to teacher evaluations and the impact on the Florida Flexibility Waiver's achievement goals. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]