This document first outlines considerations relative to a systems approach to evaluation, and then argues for such an approach to the evaluation of information retrieval systems (ISR). The criterion of such evaluations should be the utility of the information retrieved to the user, and the ISR ought to be regarded as one of three interrelated systems which include also the users and the information producers. The method suggested for describing an ISR system as a service system involves following one query through the system from first to last contact. Parameters identified for each point through the system can be described as either global or local and belong to one of five categories: contextual, serviceability, interface, information service, customer. Questions of cost-benefit and cost-effectiveness are not addressed. (WBC)