Gini on mutability

In 1912, Corrado Gini published a book in Italian entitled “Variabilità e Mutabilità” (Variability and Mutability). The first part of the book on Variability describes for the first time what became known as the Gini index for the measurement of inequality. Much less known is the second part of the book on Mutability—the study of measures of variability applied to qualitative series—most likely because the content of this part of the book was never published in English. This paper provides for the first time an abridged and commented translation of this second part of the book. We show that it amounts to a full treaty of Mutability measures predating the development of this literature by almost 40 years.