The ultimate goal of a hearing conservation program is to protect people from developing a hearing loss caused by working in hazardous noise. When all of the hearing conservation program (HCP) tasks have been completed, and all of the regulations have been checked and followed, it is important to evaluate the effectiveness of the overall hearing loss prevention program (HLPP). Is it preventing noise-induced hearing loss? Are there gaps? How can it be improved? Is the HLPP efficient and cost-effective?
There are several ways to measure the effectiveness of the program. One is to specifically evaluate changes that occur as a result of the program, like the trend over time of the number of hearing loss cases. Other outcome measures can be tracked, like the successful reduction of noise sources or exposures. Another approach is to look at the cost of delivering the HLPP, comparing it to the cost of implementing noise control to reduce the noise hazards. It can also be helpful to audit the HLPP for compliance and/or to review the company policies and practices to ensure alignment between what is on paper and what really happens in practice. A recent hearing conservation program checklist to assess effectiveness has been developed (Neitzel et al, 2017).
Conducting routine evaluations of program effectiveness is recommended. Companies choose to review aspects of the HCP at different times to spread the workload throughout the year or conduct an audit at the same time every year or every other year. Program evaluation can be done by using internal resources, contracting the service to outside subject matter experts, or through a combination of both. Finally, once the key findings are identified, the next step is to incorporate the recommendations into the HLPP.
A feature of successful HLPPs is that there is an HLPP team with one person who is designated as the HLPP leader. A quick tool to help identify the team is to complete the “Who’s Responsible?” form. Doing this exercise may reveal duplications, gaps, or uncertainties regarding who is doing what task, and provide some guidance for the next steps. The team leader can pull together the team for regular meetings to set goals, discuss issues, and evaluate the total program. Evaluating the program can be completed by the HLPP team. However, in some cases, you could choose to contract with an independent service provider to perform this service.
There are several approaches to program evaluation. Simple checklists can be used to determine if company policies and procedures comply with regulations. A program evaluation compliance checklist for OSHA can be found by clicking here.
Another approach is to identify specific outcome measures to related to program success. If the HLPP team has determined goals, then outcome measures can be used to track progress towards completing the goal. Examples of outcome measures include:
Program evaluation can be an ongoing process in terms of ensuring that tasks are completed as planned and regulatory requirements are met. However, special assessments can be scheduled periodically to dig deeper into the details. Some programs conduct annual internal audits as preparation for a potential external, unscheduled inspection.
Recommendations for improvement may be simple, such as identifying positions for hearing protection dispensers through the workspace, or more complicated, such as developing a plan to increase the completion rate for audiometric retests for workers who experience a standard threshold shift. Program changes can be complex, such as strategically planning to implement engineering control projects to reduce noise exposure over 95 dBA TWA, for example.
Operating an effective hearing conservation program costs money as well as time and energy. It is helpful to calculate the actual costs of delivering the program and compare that to the costs of reducing hazardous noise. A cost-effectiveness analysis can reveal if resources are allocated appropriately or if changes could increase program effectiveness. Some tools exist to guide cost-benefit studies, such as those discussed in this NIOSH blog.
OSHA regulation 29 CFR 1910.95 requires that employers implement an “effective hearing conservation program”. In a letter of interpretation, OSHA explained that this term means “a hearing conservation program that prevents workplace noise from producing a standard threshold shift in the hearing ability of any employees.” It is expected that employers should make an effort to evaluate whether or not the HCP is effective. However, there are no additional requirements specifying how to conduct a program evaluation.
In some cases, a checklist for regulatory compliance is conducted to ensure that all regulatory requirements are being met with the existing company policies and procedures. In a true sense, a compliance checklist is different than an evaluation of program effectiveness. However, it is a good place to start to document that the hearing conservation program is in compliance. Various compliance checklists can be found on the internet, including this one provided by NIOSH.
A hearing conservation program audit is more in-depth than a compliance checklist. This typically involves interviewing members of the management, staff, and workforce. Records can be reviewed in detail and an effort is made to identify if everyday practices are aligned with the company policies and procedures. A “deep dive” program audit can be done by an internal team or may be contracted with an external, subject matter expert.
To calculate the incidence of STS, divide the number of STS cases by the number of annual tests and multiply the result by 100.
% STS = 100 x (# of STS/ # annual tests)
For example, a company that conducted 200 annual hearing tests found 9 cases of STS. The overall per cent STS for the noise-exposed group is 100 x (9/200) or 4.5%. Tracking this number over time can help identify if the STS rate is acceptable and/or stable.
Another approach is to measure the variability within the audiometric database for workers who have been tested over multiple years. An ANSI Technical Report details a statistical procedure to identify fluctuations in the audiometric data which is an indicator of quality. High variability in audiometric thresholds for a population can be a sign of hearing change, poor quality hearing tests, or other factors that compromise the integrity of the data. This ANSI report can be purchased as a stand-alone document however it is also reproduced in the CAOHC Hearing Conservation Manual Appendix M: ANSI S12.13 TR-2002 (R2010) American National Standard Technical Report Evaluating the Effectiveness of Hearing Conservation Programs through Audiometric Data Base Analysis and can be purchased at www.caohc.org.
Oher measures can be conducted on other aspects of the hearing conservation program, like tracking the number of people in critical exposure groups, noise control efforts that result in decreased exposures, or on achieving a target for completing hearing protection fit-testing.
Here are some examples to monitor change over time:
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