News reports on the new federal census figures out today are emphasizing that California, for only the second time, did not gain enough in population to win an additional seat in the U.S. House of Representatives. But the real news about the Census Bureau's estimate of California population is just how low the number is compared to the state's own estimates.
The new census puts California's population at 37.25 million. But the state of California estimates its population at 38.8 million. That is an enormous spread between federal and state estimates -- nearly 1.6 million, enough to have a significant impact on federal spending and other formulas based on population. (And the spread is not new -- the difference between the census' annual estimates and the state's annual estimates has been slowly widening for the past decade)
What explains the difference?
Both numbers are sophisticated estimates based on different data. The feds rely on federal data (primarily tax), as well as census surveys. The state depends on housing, labor and drivers' license data.
Those different bits of data produce remarkably similar figures when it comes to population changes from births and foreign immigration. But the data produces entirely different numbers when it comes to the politically significant question of domestic out-migration -- specifically, the net number of people who leave California for other states vs. those who move to California from other U.S. states.
If you believe the Census Bureau, California is losing far more people to other states than it is gaining. (And much of this loss, according to the feds, happened in the early part of the last decade, when the number of new houses and new jobs was growing in California).
If you believe the state, the domestic out-migration is very small. The difference matters because many critics of state economic policies, particularly on the right, argue that California is driving people out of state; many on the left say such claims are overblown.
What to do? Despite the cost and bad budget times, California might be wise to invest in its own census. We need to know much more about ourselves, including how many of us there are.