Some Arizona cities among nation’s leaders in population growth

Two Arizona cities are among the top gainers in population since the last decennial count.

A new report May 21 from the Census Bureau finds that the 28,769 people who moved to or were born in Buckeye since the 2010 count was enough to rate it the second fastest-growing city of more than 50,000 in the nation at 56.6%. Only Frisco City, Texas, grew faster at 71.1%.

But nearby Goodyear came in No. 14 for growth during the same period with a 33.1% increase in population since the last census.

That’s not to say that other Arizona communities have not grown faster in the past decade. Marana, for example, added 14,464 new residents since the beginning of the decade, sufficient to compute out to a 41.9% increase.

But the Census Bureau, in ranking growth on a national level, only considers communities of more than 50,000. And if the Census estimate is to be believed, Marana needs another 970 inhabitants to reach that mark.

And even when it hits that magic number, that doesn’t automatically merit a national ranking.

So Queen Creek, with 8% growth, isn’t in the national list even with the estimate at 50,890.

In terms of pure numbers, Phoenix gained more people since 2010 than any other city in the nation, picking up what the Census Bureau figures is more than 25,330 people per year in the past decade – 72 people a day in just the last year alone.

The Census Bureau also noted that four communities in the country surpassed the 500,000 mark in 2019, including Mesa.

In some ways, the numbers are no surprise. The state’s own Office of Economic Opportunity released its own estimates for 2019 in December.

Some are pretty much spot on.

For example, the state’s office puts the population of Prescott Valley on June 30 at 46,458, versus the Census Bureau figure of 46,515.

But there are differences.

For example, the Census Bureau has concluded that the population of Tucson on that date was about 1,500 more than the state’s own figures. That’s a difference of nearly less than 0.3%.

But a difference of about 1,600 people in Casa Grande between the two estimates comes close to 3%. And the Census Bureau says Avondale has almost 4% more residents than the state’s own figures.

This works both ways. For example, while both the state and federal agencies say Benson has lost population, the Census Bureau estimate is about 3.6% less than the state figures.

The federal agency also figures that Clifton has almost 16% fewer residents than the state’s count.

And the way the Census Bureau sees it, Nogales has fewer people now than it did in 2010, a conclusion with which the state does not agree. Ditto Patagonia.

Jim Chang, the state’s demographer, said the differences come down to how each agency makes its estimates.

Both start with the official decennial count. And both then use estimates of each county’s population change.

Chang said the Census Bureau seeks to follow individual people. It uses numbers of births and deaths. But then it factors in migration, using information from the Internal Revenue Service to determine who has moved in and who has moved out.

By contrast, he said, the Office of Economic Opportunity tries to break down the population by age groups.

For example, to determine those younger than age 5 he uses birth and death records. School enrollment becomes the basis for those 5 through 17, with driver’s licenses and ID cards used to figure those up through age 64.

For those older than that, there are Social Security and Medicare enrollment records.

Then, to break down into local levels, Chang said, his agency looks to local records on housing completions or building permits.

So which numbers are more accurate?

Chang said that will become obvious once the results of the 2020 count are released about a year from now.

The results of the 2010 census showed that both the state and the feds had overestimated the number of people living in Arizona. Chang said, the Census Bureau numbers were more than 4% higher than the actual count showed; Arizona’s numbers were slightly less than 4%.

The numbers are important for more than bragging rights.

Population figures are used to divide up some forms of state aid and determine the number of seats in the U.S. House of Representatives a state receives. While that is computed using the Census figures, these annual estimates by the state provide some indication of where the growth is and who will be winners and losers after the official decennial count.