“The easiest way to get more people into the health insurance pool is to make health insurance more affordable,” he says.

The insurance industry says that’s not a good solution because premiums merely reflect underlying health care costs. But insurance officials seem warmer to some other proposals that could entice more healthy people to sign up without actually requiring them to.

One comes from Paul Starr, a health care expert and professor at Princeton University.

Starr has suggested giving people who don’t want coverage a chance to opt out. But if they choose to remain uninsured, he says, “you won’t be eligible to opt back in and get any of the benefit of the subsidies or use new health insurance exchanges or buy without pre-existing conditions exclusions.”