Quantifying and comparing the scaffold diversity of compound libraries depends on many variables, such as the specific method used to generate the scaffolds, the number of compounds in the database, and the specific distribution or frequency of the molecules in those scaffold classes. Often, scaffold diversity is measured based on frequency counts. While these metrics are correct in the way they are defined, they do not provide enough information related to the specific distribution of the molecules across the different scaffolds, particularly the most populated ones. An entropy-based metric has been proposed to measure the distribution of the molecules across different scaffolds, particularly the most populated ones, as a complementary metric for the comprehensive scaffold diversity analysis of compound data sets .