The accepted instrument for calibrating the bone-conduction section of an audiometer is the artificial mastoid. For a variety of reasons, alternative calibration methods are in general use. Three common methods are: (1) the input voltage method; (2) the real-ear threshold method using normal-hearing listeners; and (3) the real-ear threshold method using subjects with sensorineural hearing loss. The present investigation compared these methods for both accuracy and efficiency.There were no significant differences in accuracy found among the three calibration methods. Substantial differences in efficiency were noted, however. When accuracy and efficiency are considered, the input voltage method appears to be the best alternative method for calibrating the bone-conduction system of an audiometer.