Evidence quality 4.13/5
Eight-dimension review score against the quality rubric . Each dimension scored 1–5.
- D1 Source grounding
- 3/5
- D2 Source authority
- 5/5
- D3 Arithmetic
- 4/5
- D4 Uncertainty
- 3/5
- D5 Scope
- 4/5
- D6 Prose
- 5/5
- D7 Perception honesty
- 4/5
- D8 Caveat completeness
- 5/5
How the risk varies
The headline figure averages across very different situations. Here’s how the probability varies by scenario or context:
1 in 5.3 · 19%
19% average per-claim in-network denial rate (KFF, 2024); ranges 3–36% by insurer. Per filed claim, not a lifetime probability.
1 in 2.7 · 37%
37% per-claim out-of-network denial rate (KFF, 2024). Per filed claim, not a lifetime probability.
1 in 1.6 · 62%
62% initial denial rate for Social Security Disability Insurance (complement of the SSA's 38.7% FY2024 approval rate, Urban Institute). Per initial application.
Bar length and shade rank these scenarios against each other, not against other risks. The exact odds are shown beside each.
Pick challenger
Insurers denied 19% of in-network health claims in 2024 across ACA marketplace plans, according to KFF’s analysis of CMS transparency filings. The rate ranged from 3% to 36% depending on the insurer, and 37% of out-of-network claims were denied. These are not edge cases or coding errors: while administrative denials (missing information, duplicate submissions) account for a share, the sheer volume — approximately 85 million denied in-network claims in a single year out of 451 million filed — means that millions of policyholders absorb costs they expected their insurance to cover. The most remarkable statistic is not the denial rate itself but what happens afterward: only under 1% of denied claims were formally appealed (about 263,000 out of 85 million). The system functions, in practice, as a one-sided negotiation in which the insurer’s initial decision is almost always final.
Disability insurance tells an even starker story. The Social Security Administration denied 62% of initial SSDI applications in 2024, and the rate ticked up to a 64% denial rate in fiscal year 2025. At the reconsideration stage, 84% are denied again. Only at the Administrative Law Judge hearing — which takes one to three years to reach — does the approval rate climb to 51%. The multi-stage process is designed as a filter, and it works: many applicants give up before reaching a hearing, and those who persist spend years without disability income while they wait. The financial harm is not the denial itself but the gap it creates between the onset of disability and the eventual (if it comes) approval.
What none of these sources supports is a single “chance you’ll ever be denied” number for a lifetime. The published figures are all per-claim or per-application rates — 19% of in-network claims, 37% out-of-network, 62% of initial SSDI applications — not the probability that an individual, over decades and across health, auto, property, and disability coverage, hits at least one costly denial. Turning a per-claim rate into a lifetime probability would require two numbers no source provides: how many significant claims a person files over a lifetime, and what share of those end in an unresolved, costly denial. An earlier version of this entry published a ~70% lifetime estimate built from an assumed ~1% per-claim “major denial” rate over ~118 encounters; both inputs were author guesses, so we have withdrawn the figure rather than present a fabricated precision. What the data does support is stark enough on its own: a denial is common per claim, and because under 1% of denials are appealed while overturn rates among those who do appeal are much higher, the system functions as a one-sided negotiation in which most denials — defensible or not — simply stick.
Related tidbits
About 19% of in-network health claims were denied on the ACA marketplace in 2024. Fewer than 1 in 100 of those denials were ever appealed, which is part of why the figure stays high.
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.
2/4 sources independently verified verbatim against the cited source
-
[1] KFF (Kaiser Family Foundation) — Claims Denials and Appeals in ACA Marketplace Plans in 2024 Verified
Claims Denials and Appeals in ACA Marketplace Plans in 2024See all 2 Likelier entries citing this source →
- Statistic
19% of in-network claims denied in 2024 (~85 million); 37% of out-of-network claims denied; less than 1% of denied claims appealed- Excerpt
“"Of these in-network claims, approximately 85 million were ultimately denied, resulting in an average in-network denial rate of 19%. [...] Of the approximately 85 million in-network denied claims in 2024, HealthCare.gov consumers appealed at least 262,982 — an appeal rate of less than 1%." ”
- Source data from
- 2026-03-24
- Accessed
- 2026-04-24 · archived copy
- Verification
- Excerpt independently re-fetched and confirmed word-for-word against the cited source during our grounding audit.
- Calculation
- KFF's analysis of the CMS Transparency in Coverage Public Use File provides the most comprehensive data on ACA marketplace denial rates. The 19% in-network denial rate is the basis for the native estimate. The strikingly low appeal rate (<1%) suggests that the vast majority of denials go unchallenged, meaning the effective denial rate — denials that result in the policyholder bearing the cost — is very close to the raw denial rate. The 19% figure covers all claim types (administrative, medical necessity, prior auth); the subset of denials for medical necessity is roughly 5% of all denials.
- Independence
- KFF's analysis uses CMS-mandated insurer transparency filings, independent from individual insurer self-reports and from the SSA's disability claims data.
-
[2] Urban Institute — The SSA Says It's Reduced the Disability Claims Backlog. Fewer New Claims and a Higher Denial Rate Could Be Driving the Reduction
The SSA Says It's Reduced the Disability Claims Backlog. Fewer New Claims and a Higher Denial Rate Could Be Driving the Reduction- Statistic
62% of SSDI claims denied at initial application in 2024; approval rate fell to 36% in FY2025- Excerpt
“"The SSA's approval rate fell from 38.7 percent in fiscal year 2024 to an average of 36.0 percent in fiscal year 2025. While the number of approved claims remained flat at about 812,000 from 2024 to 2025, denials account for the entire increase in total decisions." ”
- Source data from
- 2025-09-12
- Accessed
- 2026-04-24 · archived copy
- Calculation
- The SSDI initial denial rate of 62% represents one of the highest denial rates in any insurance-adjacent system. At reconsideration, 84% are denied again; at the ALJ hearing level, 51% are finally approved. The multi-stage process means that a claimant who persists through all appeals has roughly a 50% chance of eventual approval, but the process takes 1-3 years — during which the claimant has no disability income. This is included as a separate data point because disability insurance denial is a distinct and severe category of financial harm.
- Independence
- The Urban Institute analysis uses SSA administrative data, independent from the KFF health insurance claims analysis which uses CMS marketplace data.
-
[3] American Journal of Managed Care — How Insurance Claim Denials Harm Patients' Health, Finances
How Insurance Claim Denials Harm Patients' Health, Finances- Statistic
Patients who experience claim denials report delayed care, medical debt, and reduced trust in the insurance system- Excerpt
“"Insurance claim denials harm patients' health and finances, leading to delayed or foregone care, unexpected medical debt, and erosion of trust in the insurance system. The financial impact falls disproportionately on lower-income and chronically ill patients." ”
- Source data from
- 2025-01-15
- Accessed
- 2026-04-24 · archived copy
- Calculation
- AJMC provides qualitative context on the downstream effects of denials. While not a quantitative source for denial rates, it documents the mechanism by which denials translate into financial harm: patients who cannot afford to pay out-of-pocket either forgo care (creating future health costs) or incur medical debt. This supports the framing of denials as a financial risk, not merely an administrative inconvenience.
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[4] American Hospital Association — Senate report scrutinizes Medicare Advantage prior authorization denials for post-acute care services Verified
Senate report scrutinizes Medicare Advantage prior authorization denials for post-acute care services- Statistic
In 2022, UnitedHealthcare and CVS denied prior authorization for post-acute care at approximately three times their overall denial rates; Humana's post-acute denial rate was more than 16 times its overall rate (U.S. Senate Permanent Subcommittee on Investigations, 'Refusal of Recovery,' Oct 2024).- Excerpt
“"In 2022, UHC and CVS denied prior authorization requests for post-acute care at approximately three times higher than the companies' overall denial rates, while Humana's prior authorization denial rate for post-acute care was more than 16 times higher than its overall denial rate." ”
- Source data from
- 2024-10-17
- Accessed
- 2026-06-14 · archived copy
- Verification
- Excerpt independently re-fetched and confirmed word-for-word against the cited source during our grounding audit.
- Calculation
- The American Hospital Association summarizes the U.S. Senate Permanent Subcommittee on Investigations Majority Staff Report "Refusal of Recovery: How Medicare Advantage Insurers Have Denied Patients Access to Post-Acute Care" (Oct 17, 2024), which analyzed over 280,000 internal documents from the three largest Medicare Advantage insurers (2019-2022). The ~3x post-acute figure for UnitedHealthcare and CVS is used as a personal_factor_multiplier: a policyholder whose claim is for post-acute care (skilled-nursing or inpatient-rehab after a hospital stay) under one of these plans faces roughly three times that insurer's own overall denial rate — a within-insurer ratio, not 3x this entry's 19% ACA in-network baseline. The Senate report attributes much of the elevation to AI/predictive systems that flag or auto-deny costly post-acute requests. The primary Senate PDF (hsgac.senate.gov) is bot-protected and returns 403 to automated fetch; this AHA summary carries the verbatim finding.
- Independence
- The underlying Senate PSI investigation used insurer internal documents obtained under subpoena, independent from the CMS marketplace data (KFF) and the SSA disability data (Urban Institute) used by the other sources.