The patient moved into a large assisted living facility in Raleigh, N.C., in 2003. She was younger than most residents, just 73, but her daughter thought it a safer option than remaining in her own home.

The woman had been falling so frequently that “she was ending up in the emergency room almost every month,” said Dr. Shohreh Taavoni, the internist who became her primary care physician.

“She didn’t know why she was falling. She didn’t feel dizzy — she’d just find herself on the floor.” At least in a facility, her daughter told Dr. Taavoni, people would be around to help.

As the falls continued, two more in her first three months in assisted living, administrators followed the policy most such communities use: The staff called an ambulance to take the resident to the emergency room.