scope:

This report specifies procedures for systematically assessing the effectiveness of hearing conservation programs (HCPs) in preventing noise-induced hearing loss based on the variability of regular monitoring audiometry results for noise-exposed personnel. Test-totest variability in hearing thresholds measured in successive audiograms is used as the basis of two statistical indicators. Criterion ranges are given for the results of these indicators as applied to populations of noiseexposed personnel followed over time.

The application of the procedures specified in this report is one facet of audiometric data base analysis (ADBA), which also includes related techniques described in Annex A.

Purpose

The goal of ADBA-to evaluate the degree of protection for populations in hearing conservation programs-is complementary to the purpose of detecting hearing changes in individual noise-exposed employees. In audiogram review the records for a person are examined to detect significant cumulative hearing change from the initial or baseline audiogram and to trigger any follow-up actions needed to increase the degree of protection for that particular person. In contrast,ADBA is a separate process of evaluating group audiometric data to monitor the degree of protection provided to the noise-exposed population as a whole, or in selected subgroups such as departments or noise exposure groups. If ADBA results show undesirable trends, the follow-up action involves changes in overall HCP policies or procedures rather than changes in the treatment of individual employees [10-12].

The purpose of this report is to define objective procedures for evaluating HCP effectiveness in preventing occupational noise-induced hearing loss in a noiseexposed population through ADBA procedures which evaluate the variability of the serial audiometric data for the noise-exposed population as a whole or for selected subgroups.

The intended users of these procedures include industrial or military personnel directly responsible for HCPs, as well as related professionals providing consulting services in support of HCPs, and public health or regulatory agency personnel interested in evaluating HCP effectiveness. These personnel can use information about HCP effectiveness to reinforce good HCP implementation, or to identify deficiencies and justify program improvements, thereby increasing the degree of protection for the noise-exposed population before many individuals show significant hearing changes.