The data used to support the New Mexico attorney general in a controversial lawsuit between the state and a nursing home chain is “unfair” towards the provider, according to an attorney involved in the case.

A report published by NPR on Thursday digs into the data collection methods used by the attorney general to analyze staffing levels in nursing homes run by Preferred Care Partners Management Group. The nursing home chain was sued by the state last April for claims of inadequate resources, poor care and improper billing.

Attorneys for the state used what’s known as “time and motion studies” — typically used in industrial engineering — to calculate how long it takes healthcare workers to complete tasks like bathing, feeding and repositioning residents. That data was then compared with the care required by the residents in the seven Preferred Care nursing homes targeted in the suit.

The results showed that it was “physically impossible” for the number of workers employed to provide the care required by the residents, according to the NPR report.

Deborah Mann, an attorney representing the chain in the lawsuit, told NPR the state’s formula “reinvents the wheel,” and clashes with the established state standard of 2.5 hours of nursing care per resident per day.

“That’s the standard that was published to the industry,” Mann said. “That’s the standard that the people who ran the nursing homes knew about. And to try to hold somebody in retrospect liable — for essentially lying — is unfair.”

The standards argued by Mann and Preferred Care are the “minimal standards, just a basic floor” and that facilities should be doing “everything they can” to meet residents’ needs, New Mexico Attorney General Hector Balderas told NPR.

One of the nursing homes targeted by Balderas’ lawsuits sued the state in return in August, claiming Balderas’ office violated the state’s public records law.