Affiliation: “Unitat d'Investigacio en Disseny de Farmacs i Connectivitat Molecular, Dep. Quimica Física”, Facultat de Farmacia. Universitat de Valencia (Burjassot), Spain.
Discerning between the concepts of difficulty and usefulness of a molecular ranking classification is of significant importance in virtual design chemistry. Here, both concepts are viewed from the statistical and practical point of view according to the standard definitions of enrichment and statistical significance p-values. These parameters are useful not only to compare distinct rankings obtained for the same molecular database, but also in order to compare the ones established in distinct molecular sets from an objective point of view.