Make sure your hearing conservation programme is run with regular evaluations. This will help you to identify trends, magnify problem areas, and drive improvement.
The ultimate goal of a hearing conservation programme is to protect people from developing Noise Induced Hearing Loss, which is caused by working in dangerously loud environments. When all of the hearing conservation programme (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 programme (HLPP). Is it actually 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 programme. One is to specifically evaluate changes that occur as a result of the programme, like the trend over time of the number of hearing loss cases. Other outcome measures can be tracked, like 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 programme checklist to assess effectiveness has been developed (Neitzel et al, 2017).
Conducting routine evaluations of programme effectiveness is recommended. Employers choose to review aspects of the HCP at different times to spread the work load throughout the year or conduct an audit at the same time every year or every other year. Programme 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.
• Audiometric database analysis
• Hearing Loss Impairment formula
A feature of a successful HLPP, is a HLPP team with one person designated as the HLPP leader. A quick tool to help identify the team is to complete the “Who’s Responsible?” form. Completing this exercise may reveal duplications, gaps, or uncertainties regarding who is doing what task, and provide some guidance for next steps. The team leader can pull together the team for regular meetings to set goals, discuss issues, and evaluate the total programme. Evaluating the programme can be completed by the HLPP team, however in some cases, you could choose to subcontract this to an independent service provider.
There are several approaches to programme evaluation. Simple checklists can be used to determine if company policies and procedures are in compliance with regulations.
Another approach is to identify specific outcome measures to related to programme 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:
Programme 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 programmes involve 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 work space, or more complicated, such as developing a plan to increase the completion rate for audiometric retests for workers who experience a standard threshold shift. Programme changes can be complex, such as strategically planning to implement engineering control projects to reduce daily personal noise exposure over 80 dB(A), for example.
Operating an effective hearing conservation programme costs money as well as time and energy. It is helpful to calculate the actual costs of delivering the programme and compare that to the costs of reducing hazardous noise. A cost-effectiveness analysis can reveal if resources are being allocated appropriately, or if changes could increase the programme's effectiveness.
The Physical Agents (Noise) Directive 2003/10/EC lays down minimum requirements for the protection of workers from risks to health and safety arising from exposure to noise and risk to hearing. The Directive explains the guiding principles of reducing or eliminating the risk of developing NIHL. In all but name, the Directive covers the key elements of hearing conservation programme.
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 the true sense, a compliance checklist is different than an evaluation of programme effectiveness, however it is a good place to start, in order to document that the hearing conservation programme is in compliance. Various compliance checklists can be found on the internet, including this one provided by NIOSH.
A hearing conservation programme 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' programme audit can be done by an internal team or may be subcontracted to an external, subject matter expert.
Outcome measures can be used to determine the effect of an intervention programme. Examples are given below. Select one or more and track the results over time to identify trends and guide programme decisions. These measures can be focused on the results of the audiometric database to track occurrences of hearing shift or hearing loss. Ideally, the occurrences of hearing shift, or STS, in the noise exposed group of workers should be the same as that of a non-noise exposure population of workers at the same facility. Using this approach would mean that hearing tests must be conducted on individuals who are not enrolled in the HCP, which may not be practical.
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 percent 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. 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.
Still other measures can be conducted on other aspects of the hearing conservation programme, 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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