This article discusses how ethnicity, gender, aging, and instrumentation affect the variability of normative wideband tympanometry (WBT) data. Understanding the mechanisms of this variability stand to improve the diagnostic accuracy in the detection of middle ear pathologies. The review of the research suggests that instrument-specific norms do not improve test performance, although the measurement of WBT at ambient peak pressure may have an impact on normative data. Small differences observed across ethnic groups in school-aged children does not warrant ethnicity-specific norms for such a population. However, differences across adult ethnic groups may warrant ethnicity-specific norms, at least for the detection of otosclerosis. The authors speculate that this latter observation in adults may be attributed to body size. Finally, maturational changes as evidenced by differences between school age children and adults do warrant the implementation of age-specific norms. It seems that further study is needed to establish normative data for WBT, particularly for body size and age. Being that the Titan offers WBT, it is well positioned as a leading platform to acquire the necessary data to establish appropriate norms, particularly with the addition of the Research module that facilitates the management of large datasets.