(Bloomberg) — Obamacare is a boon to the economy, President Barack Obama's top economic adviser said in a speech aimed at changing the tone of debate over the Patient Protection and Affordable Care Act's effects, though he offered little direct evidence.

By expanding insurance coverage, providing subsidies for premiums and helping slow the growth of health care costs, the president's signature legislative achievement has put money in Americans' pockets, Jason Furman said Thursday. Liberals should make an aggressive argument for the law's economic benefits, said Furman, the chairman of Obama's Council of Economic Advisers, speaking at the Center for American Progress.

"We can do a whole lot better than, 'our policies didn't hurt the economy while doing all these great things,'" Furman said. "In fact, they actively helped the economy, and they did it not while doing all these great things, but because of what they did in terms of coverage, in terms of cost and in terms of quality."