Advantages of experienced listeners in intelligibility testing

The use of a highly experienced, permanent panel of listeners has eliminated some of the variables of intelligibility testing and minimized many of the other objections to such testing. Variables such as training time, learning, and personnel changes are no longer significant. In addition, the problems of individual listener variation and less tangible questions of motivation and fatigue have been minimized. Consequently, measurements with low statistical variation and high repeatability have resulted; typically, less than 2 percent difference in intelligibility score has resulted from identical conditions measured nine months apart. This high reliability has also been noted in other psychoacoustic experiments in which the listeners have participated.