Subjective speech ratings need at least sixteen listeners for statistical power
Evidence
When speech signals are rated subjectively by listeners, perhaps for the evaluation of the signal provided by a mobile phone or the output from a speech-synthesis system, it is usually the quality of the signal that is of interest. The number of listeners is important, since each will have a personal opinion, and it is generally suggested that at least 16 are used to ensure that statistical analysis of the results is sufficiently powerful. However, the greater the number of listeners, the more reliable the results are. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2386
Categorization
Category: Factual Claims
- QUESTION: Who established the sixteen-listener figure, and does it hold across rating scales or only for ACR?