Mobility and Migration
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 to report where they were living in the prior year: in the same house, in a different house in the same county, in a different county in the same state, in a different state, or outside the United States (“abroad”). Annual data since 2005 are presented on Arizona Indicators 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.
Number of Migrants to Arizona
Visualization Notes:
The number of people moving to Arizona from elsewhere in the United States declined substantially from the economic boom years of 2005 and 2006 through the bottom of the recession in 2009. The figure rose slightly in 2012 and 2013 but remained considerably below the level of the prior economic cycle. The number of people moving to Arizona from another country has been lower since 2007, likely due to both economic conditions and Arizona’s employer sanctions law.
Percentage of the Population Who Did Not Move in the Last Year
Visualization Notes:
The percentage of people remaining in the same dwelling unit as the year before increased slightly nationally from 2005 through 2013, with a somewhat larger rise in Arizona. Arizona’s residents continued to be more mobile than the national average.
Percentage of the Population Who Moved in the Last Year Within County
Visualization Notes:
The percentage of residents who move from one housing unit to another within the same county over the course of a year has consistently been higher in Arizona than the national average. The proportion fell from 2005 through 2013 nationally and in Arizona.
Percentage of the Population Who Moved in the Last Year from a Different County in the State
Visualization Notes:
A smaller share of Arizona residents make an intrastate move from one county to another in any year than the national average, probably due to the large spatial size and small number of counties in Arizona. The share of intrastate movers across county lines did not change much between 2005 and 2013, either nationally or in Arizona.
Percentage of the Population Who Moved in the Last Year From a Different State
Visualization Notes:
In 2005, the percentage of Arizona residents who had migrated to the state in the past year from another state was twice the national average, but the percentage of interstate movers to Arizona fell more than the national average from 2006 to 2009. The percentages have been stable since then. Lower percentages of people make long-distance moves during economic recessions, largely due to the difficulty in finding a new job; job growth has not been strong enough in recent years to allow the percentage to rise much.
Percentage of the Population Who Moved in the Last Year From Abroad
Visualization Notes:
Nationally, the percentage of residents who had migrated from another country in the prior year was steady between 2005 and 2013 at 0.6 percent of all movers. In Arizona, the share dropped from 0.9 percent to approximately equal to the U.S. average, as the employer sanctions law and the deep recession discouraged undocumented immigrants from moving to Arizona.
Percentage of the Population Who Moved in the Last Year From a Different County in the Same State, 2009-to-2013 Average
Visualization Notes:
Between 2009 and 2013, only 1.9 percent of Arizona residents had moved from a different Arizona county in the last year, compared to a national figure of 3.2 percent moving across county lines in the same state. The proportion was at least 5 percent in Coconino, Greenlee, and Pinal counties. In contrast, due to the large difference in the population size of Maricopa County versus the balance of the state, only 1.0 percent of Maricopa County residents had moved from another Arizona county. The figure was 1.9 percent in Pima County.
Percentage of the Population Who Moved in the Last Year From a Different State or a Different Country, 2009-to-2013 Average
Visualization Notes:
The percentage of Arizona residents who had moved from outside the state in the last year (4.2 percent) was higher than the national average (2.9 percent) between 2009 and 2013. The percentage exceeded 5 percent in Cochise, Mohave, Pinal, and Yuma counties. Transfers of military personnel contributed to the high proportions in Cochise and Yuma counties. The only counties with a figure less than the U.S. average were Apache, Gila, and Navajo.
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.
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