THE SOUND frequencies to be tested in school hearing screening programs have been and continue to be the subject of discussion. Within the past few years, new concepts of screening have developed in which the single frequency of 4,000 cycles per second, or a combination of 4,000 and 1,000 cps, or 4,000 and 2,000 cps have been used in place of the standard five- and six-frequency sweep tests. Differences of opinion exist as to the effectiveness of this technique. Glorig and House1 developed oto-check, as two-frequency (4,000 and 2,000 cps) screening audiometer which they stated was 99.5% as accurate in detecting hearing impairments as the standard sweep test. In a study designed to check the validity of oto-check, Lightfoot et al2 concluded that the two-frequency screening procedure was inadequate for use in school programs and physicians' offices. They based their conclusions on the fact that of 552 ears