Assessment of the Proposed Draft American National Standard Method for Evaluating the Effectiveness of Hearing Conservation Programs

Using audiometric data, this study assessed the Draft American National Standard ANSI S12.13-1991 (DANS) method for evaluating the effectiveness of hearing conservation programs by comparing it against a standard epidemiologic method. Although the hearing conservation program of the study population was rated as "acceptable" (scale: acceptable, marginal, unacceptable) using the DANS method, the epidemiologic method found a 130% increased risk of hearing loss (relative risk = 2.3, 95% confidence interval = 0.8 to 6.5). In addition, study workers who were excluded from analyses for failing to comply with the DANS criteria were found to be at significantly increased risk of hearing loss (relative risk = 9.1, 95% confidence interval = 3.4 to 24.2). These data indicate that the DANS method may overestimate the effectiveness of hearing conservation programs and systematically exclude workers at high risk of hearing loss from analyses.