WITHIN the next month or two the office of the International Standards Organization at Geneva will release its recommendation for an international standard reference level for pure-tone audiometers.1 This standard has been long in preparation, approval, and editing, but approval by the member bodies has been virtually unanimous, with no negative votes on the final international ballot.
These new standards are based on 15 separate studies of the hearing of young adults, carried out in five different countries since 1946. The literature was carefully scanned to include all published data that were collected under appropriate audiometric conditions, by up-to-date psychoacoustic methods, with appropriate screening and motivation of subjects, and with reliable physical calibration of the instruments. Let me make it clear that the subjects were not selected because of good hearing nor were they given any initial training. They were simply screened against otological abnormality, either visible or in
HALLOWELL DAVIS. The ISO Zero-Reference Level For Audiometers. Arch Otolaryngol. 1965;81(2):145–149. doi:10.1001/archotol.1965.00750050152008