This International Standard specifies procedures and requirements for measuring the real-ear acoustical characteristics of hearing aids. Its purpose is to ensure that the same measurements made on a given hearing aid on a given human ear and a given hearing aid, following the procedures described and using equipment complying with the requirements of IEC 61669, give substantially the same results.

Measurements of real-ear acoustical characteristics of hearing aids which apply non-linear or analytical processing techniques are valid only for the test signals used and conditions employed. These measurements should be performed in accordance with the hearing aid manufacturer's recommendations as they may require specific test signals or test conditions outside the scope of this International Standard.