Source: U. S. Census Bureau, Small Area Income & Poverty Estimates for states and counties; updated every year. http://www.census.gov/did/www/saipe/.
Household income is the sum of money income received in the calendar year by all household members 15 years old and over, including household members not related to the householder, people living alone, and other nonfamily household members. Included in the total are amounts reported separately for wage or salary income; net self-employment income; interest, dividends, or net rental or royalty income or income from estates and trusts; Social Security or Railroad Retirement income; Supplemental Security Income (SSI); public assistance or welfare payments; retirement, survivor, or disability pensions; and all other income.
Since answers to income questions are frequently based on memory and not on records, many people tend to forget minor or sporadic sources of income and, therefore, underreport their income. Underreporting tends to be more pronounced for income sources that are not derived from earnings, such as public assistance, interest, dividends, and net rental income.
Per capita income is the mean income computed for every man, woman, and child in a geographic area. It is derived by dividing the total income of all people 15 years old and over in a geographic area by the total population in that area. Note -- income is not collected for people under 15 years old even though those people are included in the denominator of per capita income. This measure is rounded to the nearest whole dollar. Unlike median household income, which is estimated annually for states and counties, per capita income is derived from the American Community Survey, and thus refers to a 5-year period (see separate definition).
Families and persons are classified as below poverty if their total family income or unrelated individual income was less than the poverty threshold specified for the applicable family size, age of householder, and number of related children under 18 present (see table cited below for poverty level thresholds). The Census Bureau uses the federal government's official poverty definition.
If the total income of a person's family is less than the threshold appropriate for that family, then the person is considered poor, together with every member of his or her family. If a person is not living with anyone related by birth, marriage, or adoption, then the person's own income is compared with his or her poverty threshold.
The poverty thresholds are updated every year to reflect changes in the Consumer Price Index. The poverty thresholds are the same for all parts of the country — they are not adjusted for regional, state or local variations in the cost of living. The specific thresholds used for tabulation of income for particular years are shown at http://www.census.gov/hhes/www/poverty/data/threshld/.
Poverty status is not determined for institutionalized people, people in military group quarters, people in college dormitories, and unrelated individuals under 15 years old. These groups were excluded from the numerator and denominator when calculating the percent of persons below poverty.
Scope and Methodology:
Model-based estimates produced by the SAIPE program employ both direct survey-based estimates and regression predictions from administrative records, population estimates, and decennial census data. The regression predictions are combined with the direct sample estimates using Bayesian techniques to create estimates of income and poverty for different geographic levels. Since these are statistical estimates, they contain error, including sampling, nonsampling, and model errors. At the SAIPE website, confidence intervals are provided to show a likely range of values of the true, but unknown, figure being estimated.