Evidence of consumer confusion over health insurance continues.

A new national study of consumers by the American Institutes for Research finds that though consumers say they understand health care and insurance, many lack basic knowledge and fail to ask questions about what they’re getting in their policy before they enroll.

The news comes just weeks before open enrollment begins. And researchers say the wide gaps in literacy is a recipe for disaster.

“Because many people believe they know more than they actually do about health insurance, they may not fully understand their options before committing to a particular health plan, or they may face the shock of high out-of-pocket expenses they didn’t expect,” said Kathryn Paez, an AIR principal researcher, and study co-author.

According to the study, 42 percent say they are not likely, or only somewhat likely to review a plan’s details before signing up for coverage. Only 20 percent said they could calculate correctly how much they owe for a routine doctor’s visit.

Consumers also had a weak grasp of different plan types. About half could identify general characteristics of a health maintenance organization and 23 percent could identify the characteristics of a preferred provider organization, according to the AIR survey.

Despite this lack of knowledge, three in four consumers surveyed said they were moderately or very confident that they have the knowledge needed to use health insurance effectively.

The lack of understanding is continuing a troubling trend of confusion over the health care industry — including the Patient Protection and Affordable Care Act, industry insiders say. The administration has spent millions campaigning for the nation’s remaining uninsured to get covered under PPACA. But consumers still aren’t sure about the health care law, what’s in it and what they need to do.

Kaiser Family Foundation’s latest tracking poll, out this week, found that nearly nine in 10 of the nation’s uninsured are unaware that open enrollment begins November 15 — including 76 percent who say they don’t know when open enrollment begins and another 13 percent who name a start date other than next month.

Open enrollment runs Nov. 15-Feb. 15.

Generally, AIR’s survey found that younger people were less literate about health insurance. For example, on average those aged 22 to 34 correctly answered 55 percent of the knowledge and skills items on the survey, compared with 63 percent of 55- to 64-year-olds.

“Younger people, those who use health care less frequently, minorities, people with lower incomes and those with less education have less knowledge about health insurance because all of these groups are more likely to be uninsured,” Paez said. “And, they are the people most likely to use the health insurance marketplaces.”