Claims Denials and Appeals in ACA Marketplace Plans in 2024
Cited in 2 Likelier entries (1 risk, 1 decision).
Used in 3 entries
For each citing entry, the verbatim excerpt and Likelier's calculation notes (how the source's number was converted to the lifetime-probability framing) are shown below. Click through to read the full claim ledger.
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- 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
“"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%."”
Calculation notes
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 note: KFF's analysis uses CMS-mandated insurer transparency filings, independent from individual insurer self-reports and from the SSA's disability claims data.
Source date: 2026-03-24 · Accessed: 2026-04-24
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- Statistic
34% of ACA internal appeals succeeded in reversing the denial; fewer than 263,000 of 85 million denied in-network claims were appealed (<1% appeal rate)
“"Consumers appealed fewer than 263,000 of approximately 85 million denied in-network claims in 2024 — less than one percent. Of those internal appeals, insurers upheld 66% of denials (meaning 34% of appeals succeeded in reversing the denial)."”
Calculation notes
KFF analysis of CMS public use files for 2024 ACA Marketplace plans. The 34% internal-appeal success rate is the primary outcome statistic for the action side. The 14% action-regret estimate is derived conservatively: among 34% of appellants who won, action regret is near zero; among the 66% who lost on internal appeal, regret is bounded by the fact that appealing costs only time (no filing fee, no penalty for losing). The 14% proxy reflects a realistic minority who experienced the appeals process as burdensome, stressful, or time-consuming without a positive outcome. No direct "do you regret appealing?" survey was identified.
Source date: 2025-01-01 · Accessed: 2026-05-11
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- Statistic
Of ~85 million denied in-network ACA claims in 2024, fewer than 263,000 were appealed — a <1% appeal rate despite 34% success when appealed
“"Consumers appealed fewer than 263,000 of approximately 85 million denied in-network claims in 2024 — less than one percent. Denial rates ranged from 1% to 54% across insurers in the 2023 plan year."”
Calculation notes
The inaction-regret proxy is constructed from the gap between the appeal rate (<1%) and the success rate when appealed (34% ACA, 75% Medicare Advantage). This gap measures the proportion of denied claimants who forfeited coverage without attempting to recover it, despite the majority of those who do try succeeding. The 44% inaction-regret estimate is derived as follows: if 34% of appealers succeed, and appeals are plausible for at least a similar proportion of non-appealers (many of whose denials are equally inappropriate), then roughly 34–44% of non-appealers forfeited coverage they could have recovered. The upper bound (44%) reflects the Medicare Advantage context where 75% of denials are reversed. No direct "do you regret not appealing?" survey was identified. This is an opportunity-cost proxy, not a regret measurement.
Source date: 2025-01-01 · Accessed: 2026-05-11
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