The paper describes a system used in Nebraska in which vocational rehabilitation specialists determine who is a high need client and develop programs via a social-ecological or "person-environment" perspective. A high need client is defined as an individual who will require considerable staff support, intervention, and time. A three-phase study was initiated to determine the needs for services and resources of 18 mentally retarded clients in a community based setting. Phase I produced data on the amount of staff time devoted to individual habilitation programing and behavioral interventions. In addition, 19 client descriptors were related statistically to these two outcomes. Phase II involved statistical analyses of the data which included the finding that the amount of individualized programing was positively related to needed self-help ambulation skills and frequency of negative behaviors, whereas non-programmatic behavioral intervention was more related to frequency of negative behaviors. Significant predictor variables were identified, and behaviors were classified according to high need and moderate need. Procedures were then developed to measure those behaviors. The third phase involved reducing mismatch of clients to available programs through behavioral skill training, use of prosthetics, environmental modification, and staff assistance. A person-environment perspective model is depicted, and steps involved in matching the persons with the environment are considerd. Two case histories illustrate the system by which the mismatch of clients can be reduced. (CL)