The Auditory Brainstem Response (ABR) is an electrophysiological response used for objective hearing testing. A sound is played in the ear to stimulate nerves in the brain, and the nerve activity is then measured. The technique is particularly important for testing the hearing of infants and children as the process is relatively automatic. In New Zealand, the sounds delivered by ABR devices are calibrated to different levels than devices used in most places around the world. This is because New Zealand uses a non-standard calibration reference while other regions around the world are increasingly using a standardised calibration reference, published in ISO 389. The different references mean that hearing test results and their interpretation will also differ from those performed overseas, and are not able to be easily compared to published data. No set of reference levels are objectively right or wrong. The purpose of standardisation is to offer a common approach in order to avoid differences in sound levels across regions and across transducers like insert earphones and bone conductors in widespread use. Only with standardisation can valid comparisons be made in routine clinical as well as research activities. However, it is worth adding that in addition to reference levels being non-standard in New Zealand, the research from which they were derived has not been fully published and we believe the values contain an unexplained anomaly. Further compounding this issue, the techniques used to calibrate ABR devices are also non-standard, which has resulted in hitherto unrecognised errors. The New Zealand reference levels are sufficiently different from the standardised reference levels to cause real-world human and financial implications. For example, the higher levels used with insert earphones can cause an apparent reduction in the severity of a hearing loss, and thus differences in the way a hearing aid might be set up for anyone diagnosed with a hearing loss. Given that standardised reference levels are available via ISO 389, and given that following this standard would enable alignment of clinical and research activities in New Zealand and internationally (and alignment within New Zealand across transducers and stimuli), the rationale for continuing with non-standard calibration referencesis unclear. To resolve these problems, we recommend that New Zealand adopts the standardised reference levels in ISO 389, and the associated techniques for calibration of ABR devices.