Evaluative Usage-based Metrics for the Selection of E-journals

To measure the value of print journals, librarians have gathered a range of statistics and developed a variety of metrics. Similar work to assess the value of e-journals has just begun. This article explores the usefulness of available e-journal usage statistics and develops three metrics and three benchmarks based on those metrics. The proposed metrics build on earlier work that assesses the value of print journals, although the earlier work is modified extensively to fit the e-journal arena. The e-journal statistics and metrics are further transformed to address a completely new area of application: the evaluation of potential purchases. Statistics and metrics are used to build three benchmark measures for assessing e-journal candidates for purchase. A comparison of Science and Nature site licenses illustrates the utility of the assessment benchmarks. The benchmarks, metrics, and statistics developed here provide a reliable framework for assessing both current collections and candidate collections of e-journals. Implications for standards development are clear; content measures are desperately needed for the development of an effective suite of e-journal statistics.