As the Obama administration scrambles to corral individuals into Obamacare before today’s deadline, experts worry that first-time health insurance buyers may be in for a rude awakening once they understand the conditions and terminology contained in their policies.

A recent academic study published in the Journal of Health Economics found that just 14% of individuals who have health coverage could correctly answer all four of four basic questions about health insurance, including understanding what a “deductible” and “copay” are. If comprehension figures are that low for the insured, analysts worry what that portends for the uninsured, especially for a program as complex as Obamacare.

For example, unawareness of terms like “deductible” could prove costly. A recent analysis by Avalere Health of 19 state marketplace plans found that the average deductible for an Obamacare bronze plan–the lowest option available–is $4,300. That means big out-of-pocket costs for the newly insured.

Other studies have show similar results. A Carnegie Mellon University study finds that 86% of Americans ages 25 to 64 do not understand Obamacare.

Obamacare remains extremely unpopular with the public. A new CNN poll finds that a record low 35% of Americans approve of Obamacare.