Data Source: CDC/NCHS, National Vital Statistics System, National Health Interview Survey, and U.S. Census Bureau
The measure is estimated using a model that combines life expectancy estimates with prevalence rates of being in “good or better health and free of activity limitations”. Life expectancies are calculated using a standard demographic model that uses total population and total number of deaths by single (age group) year of age.
The health prevalence rates come from health data. Health and activity limitation status are defined based on the following two National Health Interview Survey (NHIS) variables.
(a) Health status is defined based on a question on self-assessed health of persons of all ages. Response categories include (1) Excellent health, (2) Very good Health, (3) Good health (4) Fair health (5) Poor health, (7) Refused, (8) Not ascertained, (9) Don’t know. In the population health measure, “good or better health” includes categories (1), (2) and (3). “Poor health” includes categories (4) and (5). The three categories (7), (8) and (9) are excluded from the estimation of “good or better” health.
(b) The responses to the question on “activity limitation” status are coded into the following four categories: (1)Not limited in any way (including not known if limited), (2) Limited; caused by at least one chronic condition, (3) Limited; not caused by any chronic condition, (4) Limited; not known if condition is chronic.
For the population health measure, “activity limitation” is defined by collapsing the four categories of the survey responses into the following two categories: (a) Not limited, (included in this new category are persons only in the original category [1]). (b) Limited, This new category includes persons in categories [2], [3] and [4] of the original four categories).