Earlier research [Royster et al., J. Acoust. Soc. Am. 99, 1506--1526 (1996)] has reported on a new laboratory test method to predict the amount of attenuation hearing protectors provide to workers in the real world. The subject fit method (SF) employs the use of subjects who are audiometrically competent but naive with respect to hearing protector use and who must rely only upon the manufacturer's instructions to fit a protector for testing. One unresolved issue has been the number of subjects and number of repeated tests per subject necessary to achieve the desired levels of repeatability (test--retest within a laboratory) and reproducibility (test--retest between laboratories). Attenuation data from four laboratories collected with the same protocol showed that estimates of variance for the reproducibility across hearing protectors (Bilsom Muff, E-A-R plug, EP100 plug, V-51R plug) for informed user fit (IUF) were greater than estimates of the SF variance. The estimates of variance for the repeatability across protectors and frequency were comparable between the IUF and SF conditions. The average IUF attenuations across protectors and frequency were greater than the average SF attenuations for all of the plugs.