What are the odds of dying from a medical error?
Evidence quality 4.5/5
Eight-dimension review score against the quality rubric . Each dimension scored 1–5.
- D1 Source grounding
- 5/5
- D2 Source authority
- 5/5
- D3 Arithmetic
- 4/5
- D4 Uncertainty
- 4/5
- D5 Scope
- 4/5
- D6 Prose
- 5/5
- D7 Perception honesty
- 4/5
- D8 Caveat completeness
- 5/5
Lifetime probability · lifetime, US adult
1 in 12
8.5% lifetime chance
Most people underestimate this.
range 1 in 67 to 1 in 7.1
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≈ As likely as
Perceived
Medical errors occupy an unusual place in public risk perception: most people substantially underestimate their frequency. Unlike plane crashes or shark attacks, hospital errors lack a vivid media archetype — they happen behind closed doors, are rarely coded on death certificates, and are diffused across millions of encounters. Gallup surveys on healthcare confidence show that while Americans express general trust in their doctors, few spontaneously rank medical error among leading causes of death. The 2016 Makary & Daniel BMJ paper repositioning medical errors as the "third leading cause of death" generated widespread media attention precisely because it contradicted public intuition.
Rough estimate: ~1 in 10,000 to 1 in 100,000 lifetime feels about right to most people
Source: editorial intuition, not polled
Actual
~250,000 deaths per year from medical errors in the US
US adults receiving medical care (~330 million population, ~3.09 million annual deaths)
Show derivation
Makary & Daniel (2016, BMJ) estimated ~251,454 deaths per year from medical errors, extrapolating from studies of preventable adverse events in hospitals. James (2013, Journal of Patient Safety) estimated 210,000-440,000. The Institute of Medicine's 1999 "To Err Is Human" used the lower figure of 44,000-98,000. The central estimate of ~250,000 is the most widely cited figure. Against ~3.09 million total US deaths per year (CDC 2023), medical errors would account for roughly 8.1% of all deaths. Since everyone dies exactly once, this translates to approximately an 8.5% lifetime probability that one's eventual death will be attributable (in whole or in part) to a preventable medical error. The uncertainty band is wide because: (1) the definition of "medical error" varies across studies, (2) the Makary figure is an extrapolation from a small number of studies, not a direct count, and (3) many errors contribute to death without being the sole cause. Calculation: 250,000 / 3,090,000 ≈ 0.081; adjusted upward slightly to 0.085 to account for errors in outpatient and non-hospital settings not captured in the hospital-focused studies.
Caveats: The headline figure of ~250,000 deaths per year is an extrapolation, not a direc…
The headline figure of ~250,000 deaths per year is an extrapolation, not a direct count. Medical errors are not listed on death certificates, and no surveillance system directly tracks them. The Makary & Daniel estimate has been criticized on methodological grounds: it applies adverse-event rates from small, high-acuity samples to the entire hospitalized population, and it counts cases where error "contributed to" death rather than cases where error was the proximate cause. The IOM's original 1999 estimate was 3-5x lower. The "lifetime probability" framing here is unusual — it asks what fraction of all deaths involve preventable error, which is not the same as asking "what is my risk of being killed by a medical error on my next hospital visit." The per-encounter risk is much lower. Readers should also note that healthcare simultaneously prevents far more deaths than it causes through error; the net effect of medical care on life expectancy is overwhelmingly positive.
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Makary and Daniel’s 2016 BMJ analysis estimated that roughly 250,000 Americans die each year from preventable medical errors — a figure that would make it the third leading cause of death, behind heart disease and cancer. Against ~3.09 million total US deaths annually, that implies about 8.5% of all deaths involve a preventable medical error, or roughly 1 in 12 over a lifetime. For comparison, the lifetime odds of dying in a car accident are about 1 in 112 — an order of magnitude lower.
The figure is controversial precisely because it is so large and so invisible. Medical errors do not appear on death certificates, are not tracked by any national surveillance system, and are diffused across millions of routine healthcare encounters rather than concentrated in dramatic single events. The result is a risk that most people radically underestimate. The IOM’s 1999 “To Err Is Human” report put the number at 44,000-98,000; James (2013) pushed it to 210,000-440,000. The disagreement is less about whether errors kill people than about how broadly to define “error” and how to attribute causation when a patient with multiple comorbidities dies after a preventable complication.
Where the headline number misleads: it treats “contributed to death” and “caused death” as equivalent, which inflates the count. It extrapolates from small, high-acuity hospital samples to all hospitalizations. And the “1 in 12” lifetime framing obscures the per-encounter denominator — with roughly 36 million hospitalizations per year, the per-admission death-from-error rate is closer to 1 in 140. The risk is also unevenly distributed: elderly patients undergoing complex surgery face multiples of the average, while a healthy adult visiting an outpatient clinic faces a fraction of it.
Claim ledger
Every number below is what each source reported, with the verbatim quote we relied on and how we arrived at our figure. Click any link to verify directly.
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[1] BMJ (British Medical Journal) — Medical error—the third leading cause of death in the US
Medical error—the third leading cause of death in the US- Statistic
An estimated 251,454 deaths per year in the US stem from medical error, making it the third leading cause of death behind heart disease and cancer- Excerpt
“"Based on a total of 35,416,020 hospitalizations, the researchers calculated that 251,454 deaths stemmed from medical error, translating to 9.5 percent of all deaths each year in the U.S." ”
- Source data from
- 2016-05-03
- Accessed
- 2026-04-18 · archived copy
- Calculation
- Makary & Daniel extrapolated from four studies (Healthgrades 2004, OIG 2010, AHRQ 2008, Landrigan 2010) that measured preventable adverse event rates in hospitalized patients. They applied these rates to total US hospitalizations (~35.4 million/year) to estimate ~251,000 deaths. This is not a direct count — it is a modeled extrapolation. The figure has been criticized for conflating "contributed to death" with "caused death" and for applying rates from high-acuity samples to all hospitalizations. Nevertheless, it remains the most widely cited estimate and was published in a major peer-reviewed journal. Native rate: 251,454 / 3,090,000 total US deaths ≈ 0.081. Lifetime interpretation: ~8.5% probability that any given US adult's death will involve a preventable medical error.
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[2] Journal of Patient Safety — A New, Evidence-based Estimate of Patient Harms Associated with Hospital Care
A New, Evidence-based Estimate of Patient Harms Associated with Hospital Care- Statistic
Between 210,000 and 440,000 patients per year suffer some type of preventable harm that contributes to their death in hospitals- Excerpt
“"Using a weighted average of the 4 studies, a lower limit of 210,000 deaths per year was associated with preventable harm in hospitals. Given limitations in the search capability of the Global Trigger Tool and the incompleteness of medical records on which the Tool depends, the true number of premature deaths associated with preventable harm to patients was estimated at more than 400,000 per year." ”
- Source data from
- 2013-09-01
- Accessed
- 2026-04-18 · archived copy
- Calculation
- James (2013) used the Global Trigger Tool methodology across four studies to estimate preventable hospital deaths. His upper bound of 440,000 is substantially higher than Makary's 251,000 and reflects broader inclusion criteria. The lower bound of 210,000 aligns more closely with Makary. This range (210,000-440,000) drives the uncertainty band: 210,000/3,090,000 ≈ 0.068 at the low end; 440,000/3,090,000 ≈ 0.142 at the high end. The central estimate of 250,000 sits near the lower bound of James's range and the central estimate of Makary's.
- Independence
- James's study uses different underlying data (Global Trigger Tool reviews) from Makary & Daniel's extrapolation approach. The two estimates converge on a similar order of magnitude through independent methodologies.
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[3] World Health Organization — Patient Safety Fact Sheet
Patient Safety Fact Sheet- Statistic
1 in every 10 patients is harmed in health care; more than 3 million deaths occur annually due to unsafe care globally- Excerpt
“"Around 1 in every 10 patients is harmed in health care and more than 3 million deaths occur annually due to unsafe care. The risk of patient death occurring due to a preventable medical accident while receiving health care is estimated to be 1 in 300." ”
- Source data from
- 2023-09-01
- Accessed
- 2026-04-18 · archived copy
- Calculation
- WHO's global figure of 3 million deaths from unsafe care is broadly consistent with the US estimate when scaled by population. The US (~330 million) is roughly 4% of the global population (~8 billion); 4% of 3 million = 120,000, which is lower than the US estimates but reflects lower healthcare utilization intensity in many countries. The WHO's "1 in 300" per-encounter risk figure is not directly comparable to the lifetime figure used here but provides independent corroboration that medical error is a major cause of preventable death.
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[4] Agency for Healthcare Research and Quality (AHRQ) — Measuring and Responding to Deaths From Medical Errors
Measuring and Responding to Deaths From Medical Errors- Statistic
Estimates range from 44,000-98,000 (IOM 1999) to 250,000+ (Makary 2016); measurement remains contested- Excerpt
“"Estimates of the population toll of deaths from medical error are extrapolations from individual studies in which there were very few deaths. While there is general consensus about the frequency of preventable harm in hospitals, the number of deaths that directly results from these preventable adverse events is controversial." ”
- Source data from
- 2023-01-15
- Accessed
- 2026-04-18 · archived copy
- Calculation
- AHRQ's PSNet perspective explicitly acknowledges the measurement controversy. The IOM's original 1999 estimate (44,000-98,000) would yield a lifetime fraction of 1.4%-3.2% — still substantial but much lower than the Makary/James estimates. The AHRQ commentary does not endorse a specific number but notes "general consensus about the frequency of preventable harm." This entry uses the Makary figure as the central estimate because it is the most widely cited in the peer-reviewed literature, while the uncertainty band (1.5%-14%) spans from the IOM lower bound to the James upper bound.