"Hoarseness" diagrams. "Hoarseness" diagrams illustrating graphically the distinction between normal (blue '+' symbols) and disordered (black '+' symbols) on all speech examples from the Kay Elemetrics dataset, for (a) the new measures return period density entropy (RPDE) (horizontal axis) and detrended fluctuation analysis (DFA) (vertical axis), (b) for the irregularity (horizontal) and noise (vertical) components of Michaelis , (c) for classical perturbation measures jitter (horizontal) and noise-to-harmonics ratio (NHR) (vertical) and (d) shimmer (horizontal) against NHR (vertical). The red dotted line shows the best normal/disordered classification task boundary over 1000 bootstrap trials using quadratic discriminant analysis (QDA). The values of the RPDE and DFA analysis parameters were the same those in the analysis of figures 3 and 5 respectively. The logarithm of the classical perturbation measures was used to improve the classification performance with QDA.