A measure of the 'Goodness' of hit lists obtained from chemical database searching is proposed (the G-H score). This measure takes into account both the yield (the fraction of active structures hit) and the percentage of actives that are retrieved from the database. By using variable coefficients on these terms and adjusting for the size of the hit list, a flexible but quantitative measure of hit list quality is obtained. We show the application of this measure to several published search results. We also show how the G-H score can be used to measure the quality of clustering results.