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What the new uninsured numbers don’t tell us about Obamacare

This much is clear: Obamacare has already put a major dent in the nation's uninsured rate. By just how much is less clear, and a couple of new government surveys out this morning could make the situation seem a bit more confusing.

The U.S. Census Bureau's Current Population Survey out Tuesday morning found that the nation's uninsured rate in 2013 was 13.4 percent, or about 42 million people. The Census data, though, covers the year leading up to the Affordable Care Act's coverage expansion, so it doesn't offer much information on Obamacare's impact — though it provides a baseline of the country just before the law went into effect.

Potentially making things a bit more confusing: the Census earlier in the year announced a change to how it asks about health insurance coverage in the Current Population Survey. The agency says the new questions will more accurately reflect insurance status, but it could make it difficult to compare uninsured rates between 2012 and 2013. The Census said the switch will provide a more reliable reading for the change in health insurance coverage between 2013 and 2014, the first year of the ACA's coverage expansion.

And the Census on Tuesday also released results from the American Community Survey — a separate measure of the uninsured rate — which found a .2 percentage point decline in the rate of people who did not have health insurance between 2012 and 2013.

The Census numbers came out on the same day a separate government survey measured the drop in the uninsured rate in the first quarter of 2014, when Obamacare took effect. The percentage of uninsured adults fell from 20.4 percent to 18.4 percent — or about 41 million adults — in the first three months of 2014, according to the National Health Interview Survey conducted by the Centers for Disease Control and Prevention.

The largest decrease in the uninsured rate was recorded among young adults age 19-25, from 19.8 percent in 2013 to 14.9 percent in first quarter of 2014, according to the CDC survey. States that opted for the ACA’s voluntary Medicaid expansion saw their adult uninsured rate drop 18.4 percent in 2013 to 15.7 percent in the first quarter of 2014, while those that hadn’t expanded as of last October saw “no corresponding significant decrease,” the CDC survey found.

However, that survey of nearly 28,000 people doesn’t capture the full impact of the ACA because it doesn’t account for the late surge of signups during the enrollment period. Health insurance for those people who signed up close to the enrollment deadline wouldn’t have started until April at the earliest, which was after this survey period.

Other private surveys using more current data have found larger dips in the uninsured rate since the start of the year. Gallup, for instance, found the adult uninsured rate dropped from 17.1 percent in the fourth quarter of 2013 to 13.4 percent in the second quarter this year, which was the lowest level since Gallup started measuring the uninsured rate in 2008. The Urban Institute's Health Reform Monitoring Survey has found a similar drop.

The new surveys Tuesday also come out a day after the Obama administration announced that 115,000 immigrants who purchased insurance through federal exchanges will lose their coverage by the end of this month for failing to provide documentation of their citizenship or immigration status. Another 360,000 customers risk losing part or all of their premium subsidies after September if they don't provide updated income information to the federal government. Monday's news is reminder that the coverage landscape in 2014 is still changing.

The federal surveys from the CDC and the Census are larger and more sophisticated than the private surveys — but they're also slower to report. As the Kaiser Family Foundation explains, it's probably going to take well into next year to fully understand the ACA's first year.