 |
The NHIS is a
continuous household survey of a representative sample of the US civilian
noninstitutionalized population administered by the National Center for
Health Statistics of the Centers for Disease Control and Prevention. It is a
face-to-face survey that collects information about a wide variety of health
conditions, health behaviors and access to health care. Asthma is one of
many health conditions that is included. In 1997, the NHIS was redesigned
to improve the content, simplify the survey, and reduce the questionnaire
length. The redesign involved changes both to the survey structure and
survey questions and therefore affected estimates for most health
conditions. As a result, estimates before 1997 are not always comparable to
those produced in 1997 and afterwards.
|
