Update:

The Washington Post declined to retract a "fact check" of Democratic presidential primary candidate Sen. Bernie Sanders' recent remarks on medical bankruptcies, despite a letter sent from the campaign to the newspaper, according to a screenshot posted to Twitter late Saturday by Sanders 2020 senior adviser Warren Gunnels.

The @washingtonpost refused to retract its fact check accusing Bernie of lying by saying “500,000 Americans will go bankrupt this year from medical bills.”



Author of study: "even the 530,000 figure is an underestimate of the number of people affected by medical bankruptcies" Sad pic.twitter.com/E1k9Vo33d6 — Warren Gunnels (@GunnelsWarren) September 1, 2019

Earlier:

As Democratic presidential primary candidate Sen. Bernie Sanders teased a proposal to cancel all past due medical debt and address all future medical debt in the United States, his campaign sent a letter Saturday to Washington Post executive editor Marty Baron, demanding that the newspaper retract a controversial "fact check."

Since Wednesday, the Post has come under fire for publishing a critical review of Sanders' citation of a peer-reviewed editorial that ran in the American Journal of Public Health (AJPH). Sanders had said earlier this month that "500,000 people go bankrupt every year because they cannot pay their outrageous medical bills" and "500,000 Americans will go bankrupt this year from medical bills."

The Post's Salvador Rizzo gave Sanders' recent remarks "three Pinocchios," a designation the newspaper uses for statements that have a "significant factual error and/or obvious contradictions." Despite handing down that rating, Rizzo noted that when Dr. David U. Himmelstein—the editorial's lead author and a public health professor at City University of New York's Hunter College—was asked by the Post "whether Sanders was quoting his study accurately, he said yes."

Democracy dies in darkness — and the Bernie 2020 campaign is demanding some much-needed light https://t.co/RhZ1MhJUtf — David Sirota (@davidsirota) August 31, 2019

The Post's "fact check" elicited criticism from not only members of the Sanders presidential campaign but also other reporters and media outlets. Tim Dickinson wrote Thursday for Rolling Stone:

The process by which the Post fact checker transmogrified a basically true statement into a ruling of "mostly false" is a case study in the uselessness of the political fact check as it is often practiced. Subjecting political speechmaking to this kind of nitpick is folly. The entire nature of the political enterprise is looser than that. Politicians speak to broad systemic problems. If they're sharp and persuasive, they have statistics at hand. And if their staff is any good, those statistics have reputable studies to back them up. By any meaningful measure what Sanders said is accurate for the purposes of the project. If citing a study accurately enough to satisfy its author still gets a "mostly false," it's hard to know what could possibly pass muster.

The Sanders campaign's letter to the Post's executive editor, signed by senior adviser Warren Gunnels and posted in full online, also highlighted other recent "fact checks" from the newspaper that have been scrutinized, and requested that the Post commit "to covering Senator Sanders in a fair, professional, and ethical manner that finally starts honoring the most basic standards of accuracy."

Throughout the week, Gunnels has debated the veracity of the Post's "fact check" of the medical bankruptcies remarks with Glenn Kessler—editor and chief writer of The Fact Checker at the Post as well as author of some of the other "fact checks" in question—on Twitter. Their exchange included a screenshot of a message to Post fact checker Rizzo from researcher Himmelstein, who also requested the newspaper retract the piece.

Washington Post: The study Bernie cited on 500,000 medical bankruptcies was not "peer-reviewed" Study's author: Your Washington Post "Fact Checker" article falsely claimed that my article in the American Journal of Public Health had not undergone peer review. Demands retraction pic.twitter.com/84kMzvpNLR — Warren Gunnels (@GunnelsWarren) August 29, 2019 Glenn, You gave us 3 pinocchios for citing a report showing #MedicareForAll would save $2T stating: "At the Fact Checker, we rely heavily on how a study’s author says the data should be presented." Why did you not apply that same test to the author of the bankruptcy study? pic.twitter.com/Kmxuyp8Yzb — Warren Gunnels (@GunnelsWarren) August 31, 2019

On Friday, Himmelstein and Dr. Steffie Woolhandler—another co-author of the AJPH editorial and Hunter College professor—published an op-ed on the Sanders 2020 website entitled "Medical Bankruptcy Is Real, Even if the Washington Post Refuses to Believe It." Himmelstein and Woolhandler, founders of Physicians for a National Health Program, are longtime advocates of adopting a single-payer healthcare system in the United States.

In the op-ed, they provided some details about the AJPH study and noted that "dozens of politicians and publications (including the Post itself!) have cited that study as a reliable source." Regarding the statistic at the center of the ongoing controversy, Himmelstein and Woolhandler wrote that "even the 530,000 figure is an underestimate of the number of people affected by medical bankruptcies."

"Most bankruptcies involve more than one person—an average of about 2.7 people, often including a spouse/partner and children," they explained. "That means that the 750,000 bankruptcies last year involved more than 2 million people. And even if you use the most restrictive definition of medical bankruptcy—i.e. including only debtors who 'very much' agreed that medical bills were a cause of their bankruptcy—Sanders' 500,000 figure is, if anything, too low. The right number is more like three quarters of a million."