Sept. 13, 2011

Income and Poverty Estimates

Guidance on When to Use Each Survey

When should you use income and poverty estimates from the American Community Survey 

(ACS) and the Current Population Survey (CPS)?

United States - Use the CPS

For national figures, we recommend using data from the CPS — the source of the official 

national estimates of poverty as designated by the Office of Management and Budget. It is also 

the source for widely used estimates of income.

States - Use the ACS

To compare states with each other, we recommend using the ACS one-year estimates. To 

examine the most recent state trends, use the ACS one-year estimates. The CPS has value as a 

means of examining historical trends (back more than a few years) by state. Some of the 

differences between the two sources of data (CPS and ACS) are the length and detail of 

questions, sample size, geography and reference period.

Local Areas - Use the ACS

There are three different ACS data sets available, each covering different time frames and 

different geographic areas based on population size: one-year, three-year, and five-year. The size 

of the areas being compared will determine which of these data sets you should use. Single-year 

income and poverty estimates are available for all areas with a population of 65,000 or more, 

including counties, cities and all congressional districts. Three-year estimates are available for all 

areas with a population of 20,000 or more. There are five-year estimates for the nation’s smallest 

areas, such as census tracts and block groups. When making comparisons, always use the same 

data set for all geographies, even if some areas qualify for more than one data set. For example, 

if only some counties in a state have one-year data but all have three-year data, use the three-year 

data for all. More guidance on comparisons can be found on the ACS website 

(<census.gov/acs>).

Examples of when to use CPS and ACS

Area Comparison CPS ACS

United States X

State X

- use for historical trend 

analysis 

X (use one-year estimates) 

– use for recent trends (since 

2000)
Area Comparison CPS ACS

United States with state X (use one-year estimates)

>United States with 

state/metropolitan 

area/county/place

X

State with metropolitan 

area/county/place

X

American Indian/Alaska 

native areas

X

Congressional districts X (use one-year estimates)

Metropolitan area with 

county/place

X

County with place X

Places (cities) X

Census Tracts X (five-year estimates only)

Block Groups X (five-year estimates only)

Income and Poverty Data from the ACS and CPS: Some Notable Differences

• The ACS is conducted throughout the year and respondents answer questions that pertain 

to income received in the 12 months prior to interview. The CPS is conducted in the 

spring of each year and respondents answer questions that pertain to the previous 

calendar year. 

• The ACS is primarily a mailout-mailback survey (respondents receive questionnaires in 

the mail and return them by mail after completing them). Follow-up interviews are 

conducted of those who do not respond to the mailed survey. The CPS is conducted 

entirely by trained interviewers. 

• The CPS uses a much more detailed set of questions on income.