Maxim T, et al. - Given that to date, artificial shallow vs deep probe fits are used in studies assessing the effects of calibration method on changes in probe insertion, researchers here examined the combined effects of forward pressure level (FPL) calibration of stimulus level and emitted pressure level (EPL) compensation of otoacoustic emission (OAE) level on response variability during routine (noncontrived) probe fittings in order to better simulate a clinical setting. In 20 normal-hearing young-adult individuals, they recorded the distortion component of the distortion-product OAE and the stimulus-frequency OAE at low and moderate stimulus levels across a five-octave range. Comparison of three different calibration approaches was done in each individual: (1) the conventional SPL-based stimulus calibration with OAE levels expressed in SPL; (2) FPL stimulus calibration with OAEs expressed in SPL; and (3) FPL stimulus calibration with OAEs expressed in EPL. Observations revealed no significant differences in the inter-individual variability of OAE levels across the three calibration approaches. The repeatability of OAE measurements enhances and the dependence on probe position reduces in correlation to stimulus and response calibration procedures designed to minimize the effects of standing-wave interference on both the stimulus and the OAE; this was noted even when probe shifts are small. The mid- to high-frequency region had modest but significant improvements in short-term test-retest repeatability when combined FPL/EPL procedures were used. The researchers propose that greater benefit will be achieved in a more heterogeneous group of individuals and when different testers participate in the fitting and refitting of individuals, which is a common practice in the audiology clinic. They identified no significant effect of calibration approach on OAE inter-individual variability; this may be due to a homogeneous individual population and because factors other than probe position are at play.