How common are medical billing mistakes? What the research says

No one knows what share of medical bills contain a mistake. We found no published study that checked a large, random set of patients' bills line by line. What exists are surveys of what people say they noticed, and government audits of specific kinds of claims. Here is what they found, and what they do not show.

The short answer

A 2023 report from the Consumer Financial Protection Bureau (CFPB) on older Americans notes, in a footnote, that estimates of how common medical billing errors are range from about 7 percent to 49 percent. The low end is an American Medical Association estimate that 7.1 percent of paid claims in 2013 contained an error, and the high end comes from a 2014 analysis of Medicare hospital claims reviews. Both count insurance claims, not patients' bills. A range that wide means there is no reliable single figure, so be careful with any page that gives one. The same report says older adults face "a complex billing system with a high likelihood of errors and inaccurate bills", and that many claim errors, such as missing data or incorrect billing codes, are likely avoidable or fixable.

What people say they received

• In a 2022 KFF survey, 43% of US adults said they had received a medical or dental bill in the past five years that they thought contained an error. Among adults with health care debt, it was 53%.
• About two in three of those adults said the bill was for something their insurance should have covered. Others said they were billed for services they never received, or for bills they had already paid (KFF).
• In a Commonwealth Fund survey fielded in 2023 and published in 2024, 45% of insured adults aged 19 to 64 said they had received a medical bill, or been charged a copayment, in the past year for a service they thought should have been free or covered by their insurance.

These figures measure what people noticed and believed. They do not count confirmed errors, and they do not say what share of bills had one.

What happened when people questioned a bill

• Fewer than half challenged it. In the Commonwealth Fund survey, less than half of those who reported billing errors said they challenged them. Not knowing they had the right to challenge a bill was the most common reason.
• 38% said the bill came down. Of the insured adults who challenged a bill they thought their insurance should have covered, 38% said it was ultimately reduced or eliminated (Commonwealth Fund, 2024, Exhibit 4).
• Many did not get it fixed. KFF asked adults with health care debt who thought a bill contained an error what they did next. 79% said they took some action to dispute it, but 51% said they either could not fix the disputed bill or never tried, and 32% said a disputed bill was sent to collections.
• Some held off paying. About four in ten (44%) adults with health care debt told KFF they did not pay a bill in full in the past five years because they were not sure it was accurate.