Issues in the Evaluation of Human Services Delivery

There is general agreement that human services (i.e., services that depend on direct inter personal contact between a deliverer and a client) are difficult to evaluate. This article points out some of the sources of this difficulty: first of all, the theories lying behind the delivery systems are often deficient. Second, delivery of such services is highly operator- dependent and hence often radically transformed in delivery, in ways that tend to negate the intended treatment effects. A strategy for the evaluation of human services delivery is proposed consisting of several steps, in which the underlying theory is first tested, next the ability of any system to deliver the services in question, and finally whether given delivery systems can deliver a relatively pure version of the service.