WASHINGTON (AP) — How do you convince millions of average Americans that one of the most complex and controversial programs devised by government may actually be a good deal for them?

With the nation still split over President Barack Obama's health care law, the administration has turned to the science of mass marketing for help in understanding the lives of uninsured people, hoping to craft winning pitches for a surprisingly varied group in society.

The law's supporters will have to make the sale in the run-up to an election — the 2014 midterms. Already Republicans are hoping for an "Obamacare" flop that helps them gain control of the Senate, while Democrats are eager for the public to finally embrace the Affordable Care Act, bringing political deliverance.

It turns out America's more than 48 million uninsured people are no monolithic mass. A marketing analysis posted online by the federal Health and Human Services Department reveals six distinct groups, three of which appear critical to the success or failure of the program.

They're the "Healthy & Young," comprising 48 percent of the uninsured, the "Sick, Active & Worried," (29 percent of the uninsured), and the "Passive & Unengaged" (15 percent).

The Healthy & Young take good health for granted, are tech-savvy and have "low motivation to enroll." The Sick, Active & Worried are mostly Generation X and baby boomers, active seekers of health care information and worried about costs. The Passive & Unengaged group is mostly 49 and older, "lives for today," and doesn't understand much about health insurance.

The challenge for the administration is obvious: signing up lots of the Healthy & Young, as well as the Passive & Unengaged, to offset the higher costs of covering the sick and worried.

Uninsured middle-class Americans will be able to sign up for subsidized private health plans through new insurance markets in their states starting Oct.1. Low-income uninsured people will be steered to safety net programs like Medicaid.

"The goal here is to get as many people enrolled as possible," Gary Cohen, the HHS official overseeing the rollout of the law, told insurers at a recent industry conference. Partly for that reason the first open enrollment period will continue until March 31, 2014.

Coverage under the law takes effect Jan. 1. That's also when the legal requirement that most Americans carry health insurance goes into force. Insurance companies will be barred from turning the sick away or charging them more.

The new law is mainly geared to the uninsured and to people who buy coverage directly from insurance companies. Most Americans in employer plans are not expected to see major changes.

Administration officials say they see an opportunity to change the national debate about health care. They want to get away from shouting matches about the role of government and start millions of practical conversations about new benefits that can help families and individuals.

The HHS marketing materials reveal some barriers to getting the uninsured to embrace the law.

The Healthy & Young lead busy lives and tend to be procrastinators. Plus, why would they need health insurance if they're full of vigor? The Passive & Unengaged fear the unknown and have difficulty navigating the health care system. The Sick, Active & Worried dread making wrong decisions.

Marketing for the new system will start this summer, going into high gear during the fall after premiums and other plan information becomes public.

There's already widespread concern that the new coverage costs too much, because of a combination of sicker people joining the pool and federal requirements that insurers offer more robust benefits. A recent study by the Society of Actuaries forecast sticker shock, estimating that insurers will have to pay an average of 32 percent more for medical claims on individual health policies.

The administration says such studies are misleading because they don't take into account parts of the law that offset costs to individuals and insurance companies, along with other provisions that promote competition and increase oversight of insurance rates.

Rep. Jan Schakowsky, D-Ill., who has long supported coverage for the uninsured, is predicting vindication for Obama once people see how the program really works.

"It's harder to sell what is a pretty new idea for Americans while it is still in the abstract," said Schakowsky, who represents Chicago. "I think as people experience it, they're going to love it, much like Medicare."

That will put wind in the sails of Democratic candidates. "I think it's going to be a very popular feature as far as the American way of life before too long," Schakowsky added.

But Senate Republican Leader Mitch McConnell of Kentucky says Democrats have been predicting for years that Americans would learn to love the health care overhaul and that has not happened. McConnell had his picture taken next to a 7-foot stack of "Obamacare" regulations recently to underscore his disdain.

"I agree that it will be a big issue in 2014," said McConnell. "I think it will be an albatross around the neck of every Democrat who voted for it. They are going to be running away from it, not toward it."