|Per Capita Income,
Earnings (people), and Income (people)
||Compare with Caution
The ACS collects data throughout the year on
an on-going, monthly basis and asks for a respondent's income over the "past 12 months."
Census 2000, however, collected the income data for a fixed period of time -- "during 1999"
(the last calendar year). In a comparison study between Census 2000 income data and the 2000
ACS, income collected in Census 2000 was found to be about 4 percent higher than that in the
2000 ACS. For more information on the differences of income in the ACS and Census 2000, see
Income in the American Community Survey:Comparison to Census 2000. [PDF]
The Census Bureau recommends using CPI-U-RS adjustment factors published annually by the
Bureau of Labor Statistics (BLS) to adjust 1999 median, mean, and per capita income dollar
amounts shown in Summary File 3 to 2006 dollars by multiplying the 1999 dollar amounts by the
CPI-U-RS factor of 1.21005313. Get CPI-U-RS inflation adjustment factors for other years.
Furthermore, direct comparisons of income and earnings distributions between Census 2000 and
the 2006 ACS are not possible due to inflation. Users interested in making distribution
comparisons need to inflation adjust individual income records using the Public Use Microdata
Samples (PUMS) from Census 2000.
|Compare with Caution
The weighting methodology in the 2006 ACS was
modified in order to ensure consistent estimates of occupied housing units, households, and
householders. In addition, the modification reduces the difference between estimates of
spouses and married-couple households and the difference between estimates of unmarried
partners and unmarried-partner households. In general, this shifts the estimates of
householders, spouses, and unmarried partners who are typically the higher wage earners
downward as it shifts the estimates of other members of the household upward. This shift
can lead to lower estimates of per capita income. For more information on the weighting
methodology changes see the 2006 User Notes.
Also, the Group Quarters (GQ) population is included in the 2006 ACS and not included in the
2005 ACS. Many types of GQ populations have per capita income, earnings (people), and income
(people) distributions that are very different from the household population. The inclusion
of the GQ population in 2006 could, therefore, noticeable change the per capita income,
earnings (people), and income (people) distribution compared to 2005. This is particularly
true for areas with a substantial GQ population.