THE two parties have different views of Obamacare, to put it mildly. Democrats say the Affordable Care Act will make Americans healthier and happier; Republicans that its merits pale beside those of horse manure. On May 8th Sylvia Burwell, nominated to be the next health secretary, was to face questions from the Senate. Lawmakers seemed sure to seize the chance to toss darts at each other again. This time, however, they no longer have to toss darts in the dark. Thanks to new data, the law’s effects are at last starting to be visible—albeit dimly.

On May 1st the health department released its biggest set of figures yet. This included details of more than 8m Americans who have signed up for coverage through Obamacare’s exchanges (websites where individuals shop for insurance). The official numbers have gaps, but independent analyses are helping to fill them—McKinsey, a consultancy, published new data on enrolment on May 8th. Together, these figures show that Obamacare has made progress towards its main goal: expanding coverage. However, much work remains.

The new numbers begin to illuminate two main parts of Obamacare. First, they show enrolment in Medicaid, the nearly-free health programme for the poor. Second, they show enrolment in the exchanges, which offer insurance policies that cover certain benefits and charge equal rates to the healthy and sick.

In the 47 states that have March data for Medicaid, enrolment was 8% higher than it had been in the third quarter of last year. However progress has been erratic. Obamacare offers cash to help pay for states’ expansion of Medicaid to a broader swath of the poor. In states that had expanded Medicaid in March, according to the health department, enrolment was 13% higher than average monthly enrolment in the third quarter of last year. In the states that did not extend Medicaid, mostly led by Republican governors, Medicaid enrolment grew by less than 3%.

The data for the exchanges show similarly uneven progress. That 8m enrolled is a victory for Democrats, particularly given the disastrous launch of the health exchanges in October (they crashed, and people who wanted to use them to buy insurance found they couldn’t.) The Urban Institute, a think-tank, reports that Obamacare has now enrolled 15% more people than it expected. The largest group to have obtained health cover via the exchanges seem to be those who are poor or nearly so. Some 85% of those who enrolled through the exchanges qualified for subsidies.

However other figures suggest that the exchanges enrolled far fewer people than they could have. McKinsey’s survey tracks individual insurance both on and off the exchanges. Of those eligible for an Obamacare plan, just one-quarter signed up. And of these, just one-quarter were uninsured last year (see chart). There was wide variation between states. According to the Robert Wood Johnson Foundation, a charity, Vermont enrolled 85% of those eligible for an Obamacare plan; South Dakota enrolled just 11%. States also had varied success in attracting the young. Assuming that youngsters are fitter, states where fewer of them enroll may see insurance premiums rise faster next year, since Obamacare requires insurers to cover the sick at no extra fee. To keep prices in check, the law forces healthy people (who are cheap to cover) to buy insurance or pay a penalty. Sceptics have long predicted that enrollees would be disproportionately old and sick, prompting insurers to raise prices next year, which would deter healthy enrollees, driving prices even higher, eventually creating a “death spiral”.

Education, education, education

The health department reports that 28% of enrollees are aged 18-34, but this national figure is irrelevant. Each state has its own risk pool, so future insurance prices depend on how many healthy people buy coverage in each state. In Louisiana 32% of enrollees were aged 18-34. In West Virginia, by contrast, only 19% were young, well below the national average. Insurers are preparing their prices for next year. Some states will see larger jumps than others.

If Ms Burwell is confirmed as the next health secretary, which seems likely, she will have her work cut out. The new data do, however, suggest one easy way to boost enrolment. Of those who did not buy coverage, in McKinsey’s survey, most said the insurance was too expensive. But of those who were eligible for subsidies, two-thirds didn’t realise it.

Ms Burwell would do well to continue educating Americans about the law. Obamacare arouses strong emotions. And after years of rancorous debate, few Americans yet understand how it works.