Is it working?

After six months of partisan drama over the Affordable Care Act, there’s finally enough reliable information to assess whether the law is doing what it was supposed to do. The qualified answer seems to be yes.

There have been too many controversies over the ACA to count, and it will be a long time before it becomes clear whether Obamacare, as it’s known, is smart, cost-effective policy. But the law is fulfilling its main purpose: To provide health care for more people and reduce the portion of Americans without health insurance. “What’s pretty amazing is the number of people who seem to have gotten coverage, even with all the problems,” says analyst Gary Claxton of the nonprofit Kaiser Family Foundation.

Most of the attention has been focused on the politically charged question of whether enrollment through one of the exchanges created by the law would hit thresholds predicted before the ACA went into effect. So it was a victory of sorts for President Obama when he was able to announce recently that 8 million people have enrolled in Obamacare, considerably more than earlier predictions of 6 million to 7 million.

What has gotten less attention, but is equally important, is a surge in the number of people who have gotten insurance through a source other than Obamacare so far in 2014. The upshot is that the number of uninsured Americans--which totaled around 47 million in 2013--is likely to drop sharply this year. The data is still incomplete, but there are three credible sources that all show the same trend, more or less:

Gallup. The polling firm found that the percentage of adults lacking health insurance—the uninsured rate— fell from 18% right before Obamacare went into effect last year to 15.6% so far this year.

Rand. The nonprofit research group estimates there was a net gain of 9.3 million people having health insurance from September 2013 to mid-March 2014.

The Urban Institute. This think tank has conducted polls showing the number of nonelderly adults lacking health insurance shrank by 5.4 million from September 2013 to mid March 2014.

All of this data was gathered before the surge of Obamacare enrollment that occurred right before the April 1 deadline. So the number of people with insurance is probably higher than these estimates suggest, and the uninsured rate lower.

Subsidized insurance offered through the online exchanges explains only part of the increase. Medicaid expansion also has something to do with it. In 25 states that expanded Medicaid eligibility under the ACA, as they were allowed but not required to do, the uninsured rate is 5.7 percentage points lower on average than in states that didn’t expand Medicaid. So Medicaid expansion also accounts for some of the net gain in the number of people with coverage.