Disabilities, children with: Children, who by reason of having any of the disabilities outlined in supplemental note 7, need special education and related services. Types of disabilities include the following:

• Specific learning disability: A specific learning disability is a disorder of one or more of the basic psychological processes involved in understanding or in using language, spoken or written, that may manifest itself in an imperfect ability to listen, think, speak, read, write, spell, or do mathematical calculations. This includes conditions such as perceptual disabilities, brain injury, minimal brain dysfunction, dyslexia, and developmental aphasia.
• Speech or language impairment: A communication disorder such as stuttering, impaired articulation, a language impairment or a voice impairment that adversly affects a child's educational performance.
• Other disabilities: Developmental disabilities including mental retardation, emotional disturbance, hearing impairments, orthopedic impairments, other health impairments, visual impairments, multiple disabilities, deaf-blindness, autism, traumatic brain injury, and developmental delay. There is a wide range of disabilities included in this category; they are included together here to represent cases contributing to the total not otherwise presented in this graph due to their relatively low prevalence in the population.

Doctoral degree: An earned degree carrying the title of Doctor. The Doctor of Philosophy degree (Ph.D.) is the highest academic degree and requires mastery within a field of knowledge and demonstrated ability to perform scholarly research. Other doctoral degrees are awarded for fulfilling specialized requirements in professional fields, such as education (Ed.D.), musical arts (D.M.A.), business administration (D.B.A.), and engineering (D. Eng. or D.E.S.). Many doctoral degrees in both academic and professional fields require an earned master's degree as a prerequisite. First-professional degrees, such as M.D. and D.D.S., are not included under this heading. See also First-professional degree.

Doctoral institutions: Four-year post-secondary institutions that award at least a doctoral or first-professional degree in one or more programs.

Dropout: The term is used to describe both the event of leaving school before graduating and the status of an individual who is not in school and who is not a graduate. Transferring from a public school to a private school, for example, is not regarded as a dropout event. A person who drops out of school may later return and graduate but is called a "dropout" at the time he or she leaves school. At the time the person returns to school, he or she is called a "stopout." Measures to describe these often complicated behaviors include the event dropout rate (or the closely related school persistence rate), the status dropout rate, and the high school completion rate. See also Status dropout rate.