AbstractThis paper describes an O.R. approach designed to assist management in the task of identifying and subsequently quantifying potential areas for improvement in the effectiveness of maintenance. It is argued that the information commonly collected and made available to management is inadequate when compared against the true information requirements associated with this process. A survey technique incorporating the collection and analysis of subjective data was designed as a means by which to overcome this shortcoming. This approach is described within the context of two industrial case studies. The results obtained from the case studies are discussed in detail, together with problems which arose in practice with regard to the design and implementation of the methods described.