Last week, the Census Bureau provided the first peek at the results from the 2010 census. As of April 1, 2010, there were 308.7 million people in the United States. Census Bureau Director Bob Groves also announced state population totals that are used to determine how many congressional seats each state gets. This story dominated the news headlines, but these numbers have other purposes, too.
The federal government uses these population counts to distribute federal dollars to the states. According to Andrew Reamer at the Brookings Institution, in 2008 the federal government distributed $866.5 billion in funds to the states based on the census population counts. Your state gets its share of the federal pie based on the number of people that are counted by the census. If there were $866.5 billion in funds to disperse in 2010, each person would be worth $2,807 in federal money to your state.
Note that I say "people" not "citizens." This is where Arizona may have lost as much as three-quarters of a billion dollars annually in federal funding. The Arizona state government could have easily put this money to good use, as according to the New York Times, the state faced a $2.6 billion shortfall in fiscal year 2011.
I come to this conclusion by comparing what the Census Bureau expected Arizona's population to be and what it really was -- or at least who was counted. Throughout the decade, the Census Bureau demographers estimate each state's population. The most recent estimates give a sense of what the Census Bureau thought the April 1, 2010, population of Arizona would be.
So, the Census Bureau demographers projected Arizona's population to be 6,668,079 but the actual number was 6,392,017 or 276,062 fewer people than what the Census Bureau expected to find. This was the largest shortfall of any state in absolute numbers. Since Arizona is a mid-sized state, as a percentage of the population this shortfall was nearly twice that of the next nearest state, Georgia.
So why was the Census Bureau wrong? Or were they wrong? It is not unreasonable to surmise one of two things were contributing factors: Either Arizona's undocumented population did not want to stick around in the state or they did not think it was wise to fill out a government form -- even if their confidentiality is strictly guarded by the U.S. Census Bureau. If the shortfall was due to the latter, then at $2,708 a person, Arizona lost out on $775 million in federal grants per year.
I suspect that this lost revenue is a high estimate. Likely the true number lies somewhere between zero and $775 million, as reluctance to fill out a census form was one among many contributing factors to the difference between what the Census Bureau demographers expected and what the actual number was. But, we will never know for sure since it is impossible to go back in time and count again.