Two hearing percentages can differ without contradicting each other. CDC's report first released February 7, 2017 estimated audiometric notches in about 24% of U.S. civilian, noninstitutionalized adults aged 20–69 using weighted 2011–12 examination data. A September 25, 2015 CDC summary reported conversation difficulty for 21.0% of civilian, noninstitutionalized adults aged 18 or older in a 2014 interview survey. [mm6605e3][mm6437a8]

The first measure comes from hearing tests. A notch is a pattern of poorer thresholds at specified frequencies relative to other tested frequencies. The analysis used that pattern as a proxy for noise-induced hearing loss, not a definitive determination of cause. It also found notches among people who described their hearing as excellent or good, showing that a self-rating is not interchangeable with an examination. [mm6605e3][mm6437a8]

The second measure comes from a question about following conversation when background noise is present. The reported percentage counted answers of always, usually or about half the time. It did not count every occasional difficulty, and it did not diagnose the cause. The same survey's other symptom questions had their own definitions, so they should not be bundled into a single undifferentiated hearing-loss rate. [mm6605e3][mm6437a8]

Age eligibility, collection year and measurement method all change between these sources. The later publication date does not mean the examination data were collected later. The CDC analysis neither followed individuals over time nor compared successive examination cycles. These publications share a federal evidence chain and offer complementary perspectives; subtracting their percentages would not calculate an increase or decrease in hearing loss. [mm6605e3][mm6437a8]

Source documents

  1. Vital Signs: Noise-Induced Hearing Loss Among Adults — United States 2011–2012https://www.cdc.gov/mmwr/volumes/66/wr/mm6605e3.htm
  2. QuickStats: Percentage of Adults with Selected Hearing Problems, by Type of Problem and Age Group — National Health Interview Survey, United States, 2014https://www.cdc.gov/mmwr/preview/mmwrhtml/mm6437a8.htm