Today is the first day health insurance exchanges begin enrollment through the Affordable Care Act's

Wake Forest University health economics expert Christina Marsh Dalton says the shorter enrollment time, the reduction in advertising budget from $100M to 10M and the increased premiums are likely to impact enrollment.

"Sick people are those most likely to know about the start of the enrollment period and how to sign up," Dalton says. "They have either already purchased insurance through the exchange, or they have the incentive to sign up this year because of pre-existing health needs."

Young, healthy people have little incentive to purchase insurance through the exchange. With a 90% reduction in advertising budget, Dalton says advertising is especially important in influencing those who are on the fence about purchasing insurance to get on board.

"The other piece is that average premiums are increasing as much as 35% in the mid-range coverage option. With the uncertainty of executive orders, insurers have built into their premiums the expectation that President Trump may withdraw government subsidies that encourage health care providers to enter the marketplace. The uncertainty about the ACA this year and next year will impact this enrollment period and those moving forward."

Dalton's research focuses on how health care markets work and the provision of health care goods and services.