An analysis of nearly 16,000 nursing homes reveals for-profit homes are more likely to provide inferior care than their non-profit rivals, according to a USA TODAY examination of the federal government's first ratings of the homes' performance.

The new Zagat-like rating system, released today by the Centers for Medicare & Medicaid Services, assigns homes one to five stars for quality, staffing and health inspections, plus an overall score.

The scores reflect tens of thousands of inspection records, complaint investigations and quality measures, such as how many nursing staff hours were provided each day to patients, how many patients developed bedsores and how many were placed in restraints. Much of the data were collected in 2008.

Acting Medicare Administrator Kerry Weems says offering the data in a simple five-star format should prompt "a national conversation about nursing home quality" and spur homes to improve.

USA TODAY's analysis of the data found:

• Twenty-seven percent of the USA's 10,542 for-profit homes were one-star, compared with 13% of the 4,182 non-profits.

• Nineteen percent of non-profit facilities got five stars, compared with 9% of for-profits. Most non-profits are owned by corporations, while about one-fifth are run by faith-based groups.

The USA TODAY analysis is consistent with other research, says Charlene Harrington, professor emeritus of nursing at the University of California-San Francisco and a member of Medicare's technical advisory committee for the ratings. Studies show "a lot of the for-profit homes have low staffing, and it shows up in their quality," she says.

View our searchable database of ranked nursing homes

Thomas Hamilton of Medicare, who led development of the rating system, says agency researchers worked for years to develop their formulaand assembled the advisory panel over the summer to help finalize the ratings. Results will be updated at least quarterly.

Janet Wells, of the National Citizen Coalition for Nursing Home Reform, a consumer group, says members initially opposed ratings, fearing they would be inaccurate. Now, she says, her members give the agency "high marks" for helping to distinguish bad homes from good. "It's probably going to be most useful at the extremes," she says.

Nursing home groups say they welcome efforts to spotlight good and bad performers. But the American Health Care Association, a trade group whose members include for-profit homes, asked Congress in November to urge Medicare to delay release, saying the data were "flawed."

"The public is accustomed to looking at star ratings for restaurants or hotels," says Lyn Bentley, the association's director of regulatory services. "This is way more complex than that."

Bentley would not discuss why for-profits tend to score lower than non-profits. "I don't think poor quality is acceptable regardless of who provides it," she said.

Larry Minnix, head of the American Association of Homes and Services for the Aging, which represents non-profit homes, says the ratings reflect often-subjective information but are still a good idea. "Our goal is that you should not have to worry that your mother is in a good place," he says.