The age dependency ratio expresses the relationship between three age groups within a population: ages 0-15, 16-64 and 65-plus. Higher values indicate a greater level of age-related dependency in the population. In WISH, the "dependent population" is defined as people ages 0-15 and 65-plus, while the "working age population" is defined as people between ages 16 and 64. This is consistent with the definition used by the U.S. Bureau of Labor Statistics.
There are three types of age dependency ratio. The youth dependency ratio is the population ages 0-15 divided by the population ages 16-64. The old-age dependency ratio is the population ages 65-plus divided by the population ages 16-64. The total age dependency ratio is the sum of the youth and old-age ratios. All three ratios are commonly multiplied by 100 and WISH follows this convention.
As an example, the chart below shows dependency ratios for 2011 by Hispanic ethnicity in Wisconsin. The total dependency ratio for non-Hispanics is 51.6, slightly lower than the total of 52.4 for Wisconsin. The total dependency ratio for Hispanics is higher, at 66.0. The youth and old-age dependency ratios differ dramatically between the Hispanic and non-Hispanic populations. The Hispanic youth dependency ratio of 60.7 is much higher than the non-Hispanic ratio of 29.5, while the Hispanic old-age dependency ratio of 5.2 is much lower than the non-Hispanic ratio of 22.1.
These ratios indicate that while the total age dependency in the Hispanic population is higher compared to non-Hispanics, this is entirely due to the relative youthfulness of the Hispanic population.
The total dependency ratio is calculated as:
(([Population ages 0-15] + [Population ages 65-plus]) ÷ [Population ages 16-64]) × 100
The old-age dependency ratio is calculated as:
([Population ages 65-plus] ÷ [Population ages 16-64]) × 100
The formula for the youth dependency ratio is:
([Population ages 0-15] ÷ [Population ages 16-64]) × 100
It is important to note that these definitions do not take into account labor force participation rates by age group. Some portion of the "dependent" population may be employed and not necessarily economically dependent. The Bureau of Labor Statistics addresses this through a related measure, the economic dependency ratio, which includes survey-based estimates of labor force participation rates by age group.
Age dependency ratios by state: 2000 and 2010 (PDF, 56 KB)