Data Dictionary: ACS 2012 (3-Year Estimates)
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Data Source: Social Explorer; U.S. Census Bureau
Table: T109. Median Year Structure Built [1]
Universe: Housing units
Table Details
T109. Median Year Structure Built
Universe: Housing units
Variable Label
Relevant Documentation:
Median Year Structure Built
Median year structure built divides the distribution into two equal parts: one-half of the cases falling below the median year structure built and one-half above the median. Median year structure built is computed on the basis of a standard distribution. (See the "Standard Distributions" section in Appendix A.) The median is rounded to the nearest calendar year. Median age of housing can be obtained by subtracting median year structure built from survey year. For example, if the median year structure built is 1969, the median age of housing in that area is 43 years (2012 minus 1969). (For more information on medians, see "Derived Measures.")

Question/Concept History

The 1996-1998 American Community Survey question provided a write-in space for the respondent to enter a year the structure was built. From 1999-2007 the question provided 9 pre-coded response categories, which showed ranges of years, and from 2003-2007 the response categories were updated to provide detail for recently built structures. Starting in 2008, the response category "2000 or later" and the instruction "Specify yeaf with a write-in box replaced the two categories "2000 to 2004" and "2005 or later."

Limitation of the Data

Data on year structure built are more susceptible to errors of response and non-reporting than data for many other questions because respondents must rely on their memory or on estimates by people who have lived in the neighborhood a long time.


Data on year structure built in the 2012 American Community Survey can be compared to previous ACS and Census 2000 year structure built data.