Efficiency of speech audiometry and other tests

A formula for expressing the efficiency of audiological tests is proposed: E = (vb/vw - 1)/T where vb is the variance between subjects, vw is the variance within subjects and T is the testing time. This makes it possible to compare various tests even if they require different testing times. The formula has been used on various speech tests and on pure-tone thresholds for a specific group of hearing-impaired subjects, showing that pure-tone threshold tests are much more efficient than speech tests. Some suggestions are given on how to make speech tests in noise more efficient. It is concluded that the proposed formula of test efficiency should be considered when new tests are designed in order to get quick tests which add as much information as possible.