The Developmental Disabilities Act of 1984 recognized the importance of linking service delivery to individual planning and coordination. P.L. 98-527 stated that "a developmental disability is a severe, chronic disability which… reflects the person's need for a combination and sequence of special interdisciplinary or generic care, treatment or other services which are of lifelong or extended duration and are individually planned and coordinated."
This definition was linked to the requirement that each person receiving services under the Act must have an individual habilitation plan.

Developmental Disabilities Office