Respondents were then asked the functional level of hearing in the right (HRRIGHT ) and left (HRLEFT) ear according to categories of " excellent," "good," "a little trouble hearing," "moderate trouble," "a lot of trouble," or "deaf." These variables are available for 1971, 1977, 1990-1991, 1999, 2007 and 2008.

These include:

• Quality of hearing (HEARING, 1997-2009)

• Referred to an audiologist or "hearing aid dispenser", past 5 years (HRAUD, 2007 only)

• Referred to hearing specialist, past 5 years (HRSPEC, 2007 only)

• Cause of hearing loss (HRCAUSE1,2007, 2003)

• Frustrated with hearing loss (HRFRUST, 2007 )

• Frequency hearing causes worry about safety (HRSAFETY, 2007)

• Told of hearing problem by friends or relatives (HRFAM, 2007)

• Age at beginning of adult's hearing loss (HEARDAAGE, 1999, 2002, 2007)

• Can hear and understand someone who whispers from across a quiet room (HRWHISP 1971, 1977, 1990-1991, 1999, 2007)

• Can hear and understand someone who shouts from across a quiet room (HRSHOUT 1971, 1977, 1990-1991, 1999, 2007)

• Can hear and understand if someone speaks loudly in the "better ear" from across a quiet room (HRSPEAK 1971, 1977, 1990-1991, 1999, 2007)

• Can hear and understand if someone talks in a normal voice from across a room (HRSPEAK 1971, 1977, 1990-1991, 1999, 2007)

• Trouble with hearing in presence of background noise (HRBACK, 2007 only)

In 2007, hearing problem related variables were part of a Sample Adult Hearing Supplement, (sponsored by the National Institute on Deafness and Other Communication Disorders (NIDCD), which is part of the National Institutes of Health (NIH). The hearing supplement questions were included to address the Healthy People 2010 program initiatives. Questions included:

• hearing loss related to noise exposure: see HRISKWRKEV, ever regularly exposed to loud noise on the job

• access to hearing services and assistive devices: see HRALDUSE, used assistive-listening device

• reasons for not using hearing devices when recommended: see HRAREC, hearing aid ever recommended but never used