comprehensive website with detailed information. Effectiveness & program evaluation Just as program evaluation is necessary in workplace settings, it is also an important component of educational hearing conservation programs to determine if any changes need to be made. This evaluation may consist of two main parts: assessment of students' knowledge and assessment of their skills and behaviors. To examine the level of knowledge acquired by the students, a questionnaire is often given with the expectation of an 85% competency level among students. If proficiency is too low, changes should be implemented. If the knowledge level is adequate, assessing behaviors is then necessary to see if the children are using their newfound knowledge. This evaluation can be done through classroom observation of both the students and teachers in noisy classroom environments such as music, gym, technology, etc. Other regulatory agencies The Mine Safety and Health Administration (MSHA) requires that all feasible engineering and administrative controls be employed to reduce miners' exposure levels to 90 dBA TWA. The action level for enrollment in a hearing conservation program is 85 dBA 8-hour TWA, integrating all sound levels between 80 dBA to at least 130 dBA. MSHA uses a 5-dB exchange rate (the sound level in decibels that would result in halving [if an increase in sound level] or a doubling [if a decrease.in sound level] the allowable exposure time to maintain the same noise dose). At and above exposure levels of 90 dBA TWA, the miner must wear hearing protection. At and above exposure levels above 105 dBA TWA, the miner must wear dual hearing protection. Miners may not be exposed to sounds exceeding 115 dBA with or without hearing protection devices. MSHA defines an STS as an average decrease in auditory sensitivity of 10 dB HL at the frequencies 2000, 3000, and 4000 Hz. (30 CFR Part 62). The Federal Railroad Administration (FRA) encourages, but does not require, railroads to use administrative controls that reduce noise exposure duration when the worker exceeds 90 dBA TWA. The FRA defines the action level for employee enrollment in a hearing conservation program as an 8-hour TWA of 85 dBA on certain railroads, integrating all sound levels between 80 dBA and 140 dBA. FRA uses a 5-dB exchange rate. Those employees who are always at or above 90 dBA TWA are required to wear hearing protection such that sound levels are attenuated below 90 dBA TWA.