Revisiting the Hunter Gaston discriminatory index: Note of caution and courses of change

Hunter Gaston Discriminatory Index (HGDI) is a widely used estimator of discriminatory power of genotyping methods and diversity of molecular markers in bacterial pathogens, including Mycobacterium tuberculosis. In my opinion, the index is somewhat misleading: a closer look at common practice and particular studies reveals that values in the range of 0.6 –0.9 are modest but uncritically perceived as high. I propose and discuss three courses of change: (i) to continue using HGDI but be aware of the true meaning behind its value and increase a threshold of acceptable resolution to the more adequate values of 0.90–0.99, depending on study design; ( ii) to turn to other known indices of diversity (e.g., Shannon index), in order to complement HGDI; (iii) to develop new, intuitively more realistic estimator.
Source: Tuberculosis - Category: Respiratory Medicine Authors: Source Type: research