(a) A child is classified as mentally retarded who exhibits significantly sub-average intellectual functioning and exhibits deficits in adaptive behavior which adversely affect learning. Adaptive behavior refers to age-appropriate coping with the demands of the environment through independent skills in self-care, communication and play.

(b) Measurement of adaptive behavior must reflect objective documentation through the use of an established scale and appropriate behavioral/anecdotal records. An assessment of the child's functioning must also be made in settings outside the classroom.

(c) Valid and reliable instruments appropriate to the age range must be used. If they do not exist for the language and cultural group to which the child belongs, observation and professional judgement are to be used instead.

(d) Determination that a child is mentally retarded is never to be made on the basis of any one test alone.