The median age is the age that divides the population into two equal-size groups. Half of the population is older than the median age and half is younger. Median age is based on a standard distribution of the population by single years of age and is shown to the nearest tenth of a year. (See the sections on "Standard Distributions" and "Medians" under "Derived Measures.")

A housing unit occupied at the time of interview entirely by people who will be there for 2 months or less.In Computer-Assisted Telephone Interviews (CATI) and Computer-Assisted Personal Interviews (CAPI), the data for current residence elsewhere were obtained after creating the roster of people staying at the sample unit and after asking the current residence questions. Temporarily occupied units are sample units occupied at the time of interview entirely by people who will be there for 2 months or less. At sample units where all the people are staying less than 2 months, the respondent is asked a subset of the questions from the housing section, including the question on vacancy status.

The current residence concept is unique to the American Community Survey. By using the current residence to decide for whom to collect survey information, the ACS can provide a more accurate description of an area's social and economic characteristics. Most surveys, as well as the decennial census, use the concept of usual residence. Usual residence is defined as the place where a person lives and sleeps most of the time. The census defines everyone as having only one usual residence.

Comparability

Caution should be used when comparing vacant-current residence elsewhere data between the American Community Survey and Census 2000.