Averaging hearing loss across frequencies can mask a severe dead spot.

Evidence

Consider, for example, the audiogram for damaged hearing given in Figure 2.19. Here, the average dBHL value for frequencies 250 Hz to 4 kHz would be {((10 + 5 + 5 + 15 + 60)/5) = 19 dBHL}, which indicates “no hearing handicap” (see Table 7.1), which is clearly not the case. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2360

Categorization

• SEED: Averaging metrics that obscure a dangerous extreme is a general statistical failure worth illustrating beyond audiology.