Current U.S. federal special education policy under the Individuals with Disabilities Education Act (IDEA, 2004) allows states to define their own criteria to identify young children with nonspecific delays for special education using the disability category option of developmental delay (DD), or similar terminology. Arizona is the only state to divide DD by severity of delay and this practice has not been evaluated in existing research. This study analyzed historical data from one public school district for school-age special education placements, primary disability categories, and reading and mathematics achievement for children with the unique preschool disability categories of preschool moderate delay (PMD) and preschool severe delay (PSD). Frequency analysis revealed that approximately three-quarters or more of children in the sample (n = 215) had special education placement for preschool-to-kindergarten transition, third grade, and fifth grade. Logistic regression analyses found that children with PSD were significantly more likely than those with PMD to have special education placement at every time point, and students with PSD were more than nine times more likely to be identified with severe school-age disability categories at preschool-to-kindergarten transition. There were no significant differences found for achievement at third grade, although the majority of the sample performed below grade level in reading and mathematics. The results from this study are discussed with respect to the appropriateness of having two disability category options for preschool children with delays. [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.]