Answers to the questionnaire and frequency of some outcomes (e.g., prevalence of hearing-related symptoms) were presented as proportions with 95% confidence intervals (95% CI). Differences between participants’ right and left ears in proportions of some hearing tests results (e.g., percentage of notched audiograms) were analyzed using Fisher’s exact test, whereas the differences in hearing thresholds levels between ears exposed and nonexposed to noise from headsets were analyzed using t test for dependent data or Wilcoxon singed-rank test, where applicable. Similar tests were used for comparison of HTLs in call center operators with reference data from highly screened nonnoise-exposed population as well as when analyzing the differences in audiometric thresholds between participants’ left and right ears.