SEVERAL emergency-room nurses were crying in frustration after their shift ended at a large metropolitan hospital when Molly, who was new to the hospital, walked in. The nurses were scared because their department was so understaffed that they believed their patients — and their nursing licenses — were in danger, and because they knew that when tensions ran high and nurses were spread thin, patients could snap and turn violent.

The nurses were regularly assigned seven to nine patients at a time, when the safe maximum is generally considered four (and just two for patients bound for the intensive-care unit). Molly — whom I followed for a year for a book about nursing, on the condition that I use a pseudonym for her — was assigned 20 patients with non-life-threatening conditions.

“The nurse-patient ratio is insane, the hallways are full of patients, most patients aren’t seen by the attending until they’re ready to leave, and the policies are really unsafe,” Molly told the group.

That’s just how the hospital does things, one nurse said, resigned.

Unfortunately, that’s how many hospitals operate. Inadequate staffing is a nationwide problem, and with the exception of California, not a single state sets a minimum standard for hospital-wide nurse-to-patient ratios.