The purpose of this agreement is to provide funding for scientific and technical support as well as quality assurance of three large audiometric examination surveys funded by NIDCD. These health surveys are: (i) The National Health and Nutrition Examination Survey (NHANES), (ii) Age, Gene/Environment Susceptibility Study-Reykjavik Study (AGES-RS), and (iii) the Early Childhood Longitudinal Study - Kindergarten Class of 2010/2011 (ECLS-K:2010/2011). The Audiometry Components of all three health examination surveys were previously developed by NIDCD in collaboration with NIOSH and other consultants. NIOSH collaborated on the design of the experimental protocol and provided the equipment specifications, oversight of maintenance and calibration, technician training and oversight, operations manual development, and quality assurance for the NHANES. As well, NIOSH provided similar support to AGES and ECLS-K:2010/2011, including setting-up training sessions and observing/monitoring technical competence in obtaining audiometric measurements, technical assistance as needed, and limited quality assurance. The NHANES scientific goals are to establish a statistically accurate, demographically representative baseline on the general health (including Hearing Health) of the U.S. population. NHANES is now a continuous survey and while general health issues are always under investigation such as height, weight and blood pressure, there are also elements that track individual health outcomes that move in and out of the NHANES as it cycles. NHANES consists of two major components: the household interview and the physical examination in the NHANES Mobile Examination Centers (MECs) that are set up in various areas around the country. The data from the NHANES elements are collected, weighted, and made available to the government and the public as a database on which analysis may be performed. Recently, the data have been released every two years with collaborating agencies receiving the data six months prior to the public release of the data sets. The AGES-RS scientific goals are: 1) to identify genetic and new risk factors for selected diseases including atherosclerosis, cognitive impairment, dementia, stroke, hearing loss, visual impairment, sarcopenia, osteoporosis, and obesity, 2) to characterize phenotypes for these diseases and conditions, and 3) to identify contributory molecular markers associated with these conditions. The proposed ECLS:K-2011 audiometry protocol for the third-grade data collection includes four components: pre-test questions, otoscopy, wideband reflectometry with tympanometry, and pure tone audiometry: (1) Pre-Test Questions: Children will be asked a series of short questions regarding conditions which could affect the test results (cold or earaches, noise exposure within past 24 hours, presence of pe tubes, and whether one ear is better than the other);(2) Otoscopy: Children will receive a brief visual examination of the ear, primarily to assure a clear sound path. In addition, the technicians will note the presence of excessive cerumen or any other gross abnormality which could affect interpretation of audiometric findings. The otoscopic exam will not be diagnostic;it will simply be observational;(3) Wideband Reflectometry, including Tympanometry: An automated wideband reflectometric/tympanometric evaluation of the middle ear will be conducted bilaterally. Analysis and interpretation of the results will be done remotely;(4) Pure Tone Audiometry: Pure tone air conduction thresholds will be obtained bilaterally at 1000, 2000, 3000, 4000, 6000, and 8000 Hz insofar as time and the child's attention permits. A retest threshold will be obtained in both ears at 2000 Hz as a measure of test reliability. The thresholds will be obtained manually using a modified Hughson-Westlake technique. The first test ear will be alternated to avoid learning effect bias in the thresholds. Frequencies will be tested in a specified order to obtain the more important frequency data first in case time or the child's attention runs out before all frequencies are completed. All three health surveys share similar hearing exam components, developed collaboratively by NIDCD, NIOSH, NCHS, WESTAT, the Icelandic Heart Association Research Institute, and the Department of Educations, National Center for Education Statistics. The hearing component consists of: 1) a set of questionnaires relating to hearing, noise exposure, and other factors relating to hearing, and 2) audiometric examinations consisting of otoscopy, acoustic immittance (bilateral tympanometry or wide-band reflectometry and screening for ipsilateral acoustic reflexes at 1000 and 2000 Hz), and pure-tone, air-conduction audiometry to determine the hearing thresholds in each ear at several frequencies, such as 500, 1000, 2000, 3000, 4000, 6000, and 8000 Hz. A repeat threshold test is obtained at 1000 Hz or 2000 Hz as a measure of test reliability. When significant inter-ear differences are found, then retests may be performed using insert earphones to maximize the inter-aural attenuation rather than using a noise masker of the non-test ear to obtain what is referred to as masked threshold in the in the test ear to avoid recording of a shadow audiogram from the better non-test ear.