Enroll America volunteers Laura Botero and Cruz Arana prepare for an afternoon of door-knocking in Miami Beach, Fla. (Sandhya Somaskehar / The Washington Post)

Last week, I wrote about Enroll America’s plan to go door-to-door to urge uninsured people to sign up for health insurance, in some cases returning a half-dozen times to convey the message. But will a knock on the door – or eight – be enough?

Maybe not, according to Stan Dorn, a senior fellow at the Urban Institute, whom I quoted in the piece and who is skeptical of such efforts. He thinks the only way to get large numbers of people signed up quickly is to actually do the signing up for them.

"It’s human nature not to complete forms or paperwork," he said. "The initiatives that have succeeded in enrolling large numbers of people have eliminated the need for consumers to fill out paperwork."

In our conversation, he cited a few studies to illustrate his point, including one from 2005 that examined company 401(k) plans. When workers had to fill out paperwork before the accounts were created, about 33 percent of workers participated, he said. But participation spiked to 90 percent when companies automatically established the accounts, with an option for workers to opt out.

He also pointed to some experiments looking at H&R Block's efforts to help their tax clients enroll in public benefits. In one, the tax preparation company filled out the paperwork for clients eligible for SNAP. As helpful as it was to simply fill out the forms, participation in the food assistance program was 80 percent higher when the company took the extra step of submitting the paperwork on the clients' behalf.

Recent successful efforts to get large numbers of people signed up for benefits have relied heavily on automatic enrollment and in-person assistance, he said. During the health care overhaul in Massachusetts, about 1 in 4 of the state's newly-insured residents were auto-enrolled because they were already in the state's "free care pool" database, he said. Among consumers for whom applications were required, more than half were completed by providers and others acting on the consumers' behalf.

Similarly, four out of five enrollees in the Medicare Part D subsidy program were automatically enrolled because state and federal agencies already had their eligibility information. It helped the program achieve 74 percent participation within six months.

Fans of the door-to-door approach have their own research to back up their activities, saying their programs are modeled on successful efforts to enroll people in the Children's Health Insurance Program, CHIP, over the years.

Of course, under Obamacare, there will be a healthy dose of human help in the form of thousands of so-called navigators, in-person assistants, brokers and others who will be trained to guide people through their options -- over the phone, on the marketplace Web sites, at community health centers and elsewhere. The administration has worked hard to develop a simple-as-possible application form. And Enroll America's job is simply to steer people to places where they can get the kind of help Dorn is talking about.

But it's hard to say if that will be enough to overcome human nature to be lazy about pesky paperwork.