Significant Developmental Delays (SDD)

Significant Developmental Delays (SDD)


The term significant developmental delay refers to a delay in a child’s development in adaptive, behavior, cognition, communication, motor development, or social development to the extent that if not provided with special intervention, it may adversely affect his/her educational performance in age-appropriate activities. The term does not apply to children who are experiencing a slight or temporary lag in one of more areas of development, or a delay which is primarily due to environmental, cultural or economic disadvantage or lack of experience in age-appropriate activities. The SDD eligibility may be used for children from ages three through seven, and in no instance later than the end of the school year in which the child turns eight.


Initial eligibility must be established, and an IEP in place, on or before the child’s 5th birthday. SDD eligibility is determined by assessing children in five skill areas— adaptive development, cognition, communication, physical development (gross and fine motor), and social/emotional development. Any child, ages three through five, who scores at least two standard deviations below the mean in one or more of the five areas, or 1 standard deviations below the mean in two or more areas, meets eligibility requirements for SDD.

The application of professional judgment is a critical element at every stage of eligibility determination: as test instruments are selected, during the evaluation process, in the analysis of evaluation results, as well as the analysis of error patterns on standardized and teacher made tests, etc. In summary, the application of professional judgment is a critical part of the entire eligibility process.

To continue eligibility, students must have their eligibility reviewed every third year, at which time they must score two standard deviations below the mean in at least one area to continue eligibility.