A measure for the assessment of resource use in information services provides an application within the information services area of the . long tail concept. The analysis quantifies the long tail concept and is applicable to all libraries and information services, independent of their size and circulation properties. The paradigm of the Lorenz curve and the Gini coefficient from macroeconomics is adapted in the context of information services. The Gini coefficient examines the skewness of the Lorenz curve against an ideal cumulative distribution that is represented by a 45-degree line. In this context, the Lorenz curve depicts the cumulative percentage of collection items versus the number of loans and identifies the different levels of library resource use on the part of users by measuring how close the Gini coefficient is to the unity (i.e., the Gini of the 45-degree line is identified).