Median Home Value
The American Community Survey (ACS) has been conducted on an ongoing basis for the entire country since 2005. Annually, calendar-year ACS results are released for areas with a population of at least 65,000. Due to the small sample size, single-year estimates are not available for less-populous areas. Combined estimates for three years of data are available annually for areas with a population of at least 20,000; five years of data are combined for less populous areas. The substantial sampling error present in the ACS is discussed in the data quality comments section below.
The ACS questionnaire asks respondents who own their home to estimate how much the home would sell for if it were for sale. The Census Bureau calculates the median value, which is presented on Arizona Indicators. Annual data since 2005 are presented for the United States and Arizona, but data for each of the 15 Arizona counties are limited to a five-year average due to the substantial sampling error.
U. S. Department of Commerce, Census Bureau http://factfinder2.census.gov/faces/nav/jsf/pages/index.xhtml. Annual ACS estimates are released in September; five-year averages are available in December.
The Census Bureau publishes the ACS sampling error with every estimate, expressed as the margin of error with 90 percent confidence. The following is an example:
The estimate of the poverty rate in Maricopa County in 2009 was 15.2 percent, with a margin of error of + or – 0.6 percentage points. The interpretation is that there is a 90 percent likelihood that the actual poverty rate was within the confidence interval of 14.6 percent to 15.8 percent. A one-in-ten chance exists that the real rate was outside this range.
For the nation and other very populous areas, the annual ACS estimates are highly accurate. For moderately populous areas such as Arizona, sampling error is moderately large, so caution is urged in using the annual ACS data for the state. The sampling error for less populous areas, such as most of Arizona’s counties, is quite large, even when using five-year averages. Thus, considerable caution is urged in using the five-year ACS data for counties other than Maricopa and Pima.
The published margin of error should be taken into consideration when deciding whether to use a result from the ACS. Whether the reported sampling error is too large depends on the user’s purpose for accessing the data and on the volatility of the measure over time and across geographic areas.In addition to the sampling error, respondents may not be aware of their home’s value.
Median Value of Owner-Occupied Housing
Visualization Notes:
Annual estimates of home values show that home prices rose considerably during the mid-2000s but dropped through 2012. The real estate boom and bust of the 2000s was much more extreme in Arizona than the national average. The median value in Arizona went from 1 percent above average in 2000 to 28 percent higher than the U.S. average in 2006 but fell to 12 percent below average in 2012. Home prices rose more in 2013 in Arizona than nationally.
Median Value of Owner-Occupied Housing, 2009-to-2013 Average
Visualization Notes:
Median home values vary widely across Arizona. Much of the observed differences from county to county result from differences in the quality and size of the housing rather than reflecting geographic differences in prices of comparable homes. For example, manufactured housing units, which tend to have values much lower than site-built homes, make up a considerable proportion of the housing units in some counties.
During the 2009-to-2013 period, the median value reported in Arizona was 7 percent lower than the national average of $176,700. The median value was 25 percent above the national average in Coconino County and slightly above average in Yavapai County, but was only about half of the national average in Apache, Greenlee, and La Paz counties.
Data Source
U. S. Department of Commerce, Census Bureau http://factfinder2.census.gov/faces/nav/jsf/pages/index.xhtml. Annual ACS estimates are released in September; five-year averages are available in December.