The Jan. 29 editorial “The real problem with Mr. Sanders” alleged that Sen. Bernie Sanders’s (I-Vt.) health-care plan “rests on unbelievable assumptions about how much he could slash health-care costs.” That dismissive claim was based on a deeply flawed analysis by Kenneth Thorpe, an Emory University professor and former Clinton administration official who, like Democratic presidential candidate Hillary Clinton, has done a recent flip-flop on the facts about single-payer.

So what has changed? In 2003, Thorpe calculated that single-payer would achieve huge administrative savings — more than 10 percent of total health spending, equivalent to $350 billion this year alone. Now he has cut that estimate by more than half, even though the costs of bureaucracy in the United States have continually climbed, while they’ve remained low in single-payer nations.

Thorpe previously predicted that single-payer would cause a modest uptick in the utilization of care. Now — despite the fact that fewer are uninsured — he has decided there would be a huge increase.

Finally, Thorpe says nothing about savings on drug prices, despite the fact that every nation with a national health-insurance program gets discounts of about 50 percent.

The old Kenneth Thorpe — like the old Hillary Clinton — acknowledged the facts about single-payer. The new one ignores them. The editorial board should know better.

David U. Himmelstein and Steffie Woolhandler, New York

The writers are professors of health policy and management at the City University of New York School of Public Health and lecturers in medicine at Harvard Medical School.