In rating a nursing home, the Centers for Medicare & Medicaid Services first ranks the relative performance of all certified facilities within a state based on the unannounced health inspections that the state conducts for CMS about once a year. The top 10 percent of homes receive five stars, the bottom 20 percent get one star, and the remaining 70 percent is divided equally among the two-, three- and four-star categories, according to Dr. John Lambrukos, certification coordinator for the state health department's Health Facilities Administration.

Those health inspection ratings are then modified up or down, based on how a home scores on staffing levels and a variety of quality measures, to come up with an overall rating. The data that goes into the ratings, including results of health inspections, are posted on medicare.gov/nursinghomecompare.

Because of how the ratings are compiled, Lambrukos said, it's difficult to objectively compare how New Hampshire homes match up with those in other states.

“The very same health inspection score in another state may actually rate differently,” he said. “A two-star in New Hampshire may be a three-star in another state.”

He suggests families dig deeper on the website to view previous health inspections and other quality measures to get a more complete picture. And he stressed the CMS ratings “can't substitute for a visit to the facility.”