His plugged-in friends said he was a fool not to buy health insurance on the federal marketplace.

Mark Gaines knew they were right. He was, after all, a 26-year-old law school graduate. But if a judge had asked him for a summation of the Affordable Care Act last fall, it would have been a one-sentence brief.

“I didn’t know anything about it,” said Gaines, who lives in South Philadelphia and was working part-time. “I knew that it was going to make [insurance] open to everyone and make it cheaper.”

Then, one frigid day in early January, a friend forwarded an e-mail. The University of Pennsylvania was recruiting educated people ages 19 to 30 who wanted to purchase insurance through the Healthcare.gov website. Gaines volunteered.

The three-month study was the idea of Charlene Wong, 31, a pediatrician at Children’s Hospital of Philadelphia. Wong knew just how confusing and challenging buying insurance for her own family was, and she is a health policy researcher. What, she wondered, was it like for young adults doing it for the first time? Even more intriguing, what changes might the digital natives suggest to make the website more user-friendly?

The results, published in the Annals of Internal Medicine, recommended six changes: Rename “catastrophic” coverage; identify dental coverage as a separate purchase early on; create an easily accessible glossary of terms with concrete examples; clearly explain that tax credits in the form of premium subsidies and cost reductions in deductibles, copays, and coinsurance are linked – in very different ways – to silver-level plans; prominently mention that preventive care is free and part of every plan on the site; and reposition tools that are already there.

“They are relatively small changes that would improve the understandability and usability of the website,” said Wong, who is a Robert Wood Johnson Foundation Clinical Scholar, a competitive program that trains physicians in health policy and community research.

The project, which involved six researchers from various Penn schools, began in January, after most of the website’s bugs had been fixed. It ended when open enrollment closed on March 31.

The team watched the 33 subjects make their way through the website. They were told to navigate as they would if they were at home – including talking to themselves out loud, Wong said, “so we could capture their reactions in real time.”

Then they were asked a series of open-ended questions about their impressions. It turns out that when it comes to health insurance, young, tech-savvy adults are not all that different from old Luddites.

“I didn’t expect [the site] to be easy, but I didn’t expect it to be a labyrinth,” said Gaines, who had imagined that Healthcare.gov would be like shopping online – as the Obama administration had pitched it.

Wong said “a lot” of the participants were surprised that the site didn’t use their income information to recommend options. The panoply of plans left them overwhelmed.

“I could buy health insurance, yes, but if I don’t understand something I’m not going to buy anything,” Gaines said.

Wong said the group recommended that the website tailor offerings based on consumer preferences. For example, filters could suggest plans based on how much a consumer wants to pay in premiums, or whether she wants dental coverage or a health savings account.

“They pointed to all these other online shopping websites where you are able to do that and they said, ‘Why can’t they do that here?’ ” Wong said.

Participants also wanted the insurance industry to clean up its language. Terms such as deductible and coinsurance should have “instantly accessible glossary definitions paired with concrete examples for complex cost concepts,” the authors wrote.

And then there’s catastrophic coverage. Participants found the term confusing or frightening – prompting them to ignore a category that was created largely for their demographic.

“I thought it was the most extreme health insurance, but it is actually one of the simplest,” Gaines said.

The research team is using its contacts to make sure the findings get to the right people in Washington while the website is being redesigned in advance of the start of the next open-enrollment period Nov. 1.

So, how many of the young adults actually bought coverage? That’s a secret, the subject of Wong’s next paper.

Gaines, for one, did not. But he does understand the process a lot better now.

“I want health insurance, but I’m not going to choose a plan impulsively,” he said.