Prior Authorization Metrics Provide New Insights into Insurer Practices, but Gaps Remain
The use of prior authorization by health insurers has come under increased scrutiny in recent years, as nearly 7 in 10 insured adults say prior authorization is a burden when it comes to getting health care. Health insurers use prior authorization to reduce the use of low-value or unnecessary care, and in the complex and fragmented U.S. health care system is one of the primary tools used to restrain costs. Nevertheless, this practice may result in delays or denials in receiving necessary care, as well as administrative burdens for patients and providers.
In 2024, the Centers for Medicare and Medicaid Services (CMS) published a final rule aimed at streamlining and automating the prior authorization process for almost all insurance programs it oversees: Medicare Advantage, Medicaid and CHIP fee-for-service and managed care plans, and Affordable Care Act (ACA) Marketplaces on the federally facilitated exchanges (HealthCare.gov). As part of these requirements, every year, payers in these programs are now required to publicly post on their websites specified prior authorization metrics, including approval and denial rates and response times, aggregated for all medical items and services (excluding prescription drugs) for the previous calendar year.
Insurers were required to post the first year of data, for the 2025 calendar year, by March 31, 2026. KFF collected and analyzed these metrics from the largest insurers in most market segments for which reporting is required, including Medicare Advantage, Medicaid managed care, and the Affordable Care Act (ACA) federally facilitated Marketplace. This issue brief summarizes the data by market segment and insurer and discusses the challenges interpreting the data as well as emerging policy changes that may address some of them.
Key Takeaways
- Medicare Advantage insurers denied 12% of standard prior authorization requests, Medicaid managed care insurers denied 14%, and ACA Marketplace insurers denied 18%. Denial rates for expedited requests were slightly lower. However, the aggregated approval statistics do not allow for further analysis into which services are being denied.
- Prior authorization denials are rarely appealed, but when they are, a considerable share are overturned. Sixty-seven percent of prior authorization denials were overturned upon appeal in Medicare Advantage, 47% were overturned upon appeal in Medicaid managed care, and 43% were overturned in the ACA federally facilitated Marketplace.
- Median response times in all markets were about 1 day for standard prior authorization requests, and about half a day for expedited prior authorization requests for Medicare Advantage, and approximately 1 day for Medicaid managed care and the ACA Marketplace. Insurers are not required to report response time ranges or differences by service category.
- Despite the regulatory intent to make insurer prior authorization practices more transparent, difficulty locating and interpreting metrics on insurer websites and gaps in how (e.g., a standardized template that insurers are required to use) and what metrics (e.g., denominators and breakouts by service category) must be reported limit the usability of this information directly by the public.
Overview of the 2024 Regulation’s Prior Authorization Metrics Requirements
The regulation states that the overall goal of this public reporting requirement is to promote “accountability for payer prior authorization practices” and envisions consumers using the data when shopping for health insurance. The regulation requires payers to which it applies — Medicare Advantage organizations, Medicaid and CHIP fee-for-service and managed care plans, and insurers on the ACA federally facilitated Marketplace (FFM), hereafter collectively referred to as insurers — to provide a list of all medical items and services that require prior authorization (excluding prescription drugs) and report the following metrics aggregated for all medical items and services (excluding prescription drugs) for each line of business:
- Percentage of standard and expedited prior authorization requests that were approved and denied
- Percentage of standard prior authorization requests that were approved after appeal (i.e., overturned denials)
- Percentage of all prior authorization requests where review timeframes were extended and the request was approved
- Average (i.e., mean) and median timeframes between submission of a prior authorization request and determination for standard and expedited prior authorization requests
Additional metrics were made optional, including:
- Percentage of expedited prior authorization requests that were approved after appeal
- Percentage of prior authorization requests where decision timeframes were extended and then the requests were approved, broken out by standard and expedited requests
- Percentage of prior authorization requests approved within 7 days for standard requests and 72 hours for expedited requests
- Numeric counts for metrics, including total number of requests and appeals received
Describing “Standard” and “Expedited” Prior Authorization Requests
The 2024 regulation refers to “standard” prior authorization as non-expedited, non-urgent requests and to ‘‘expedited’’ prior authorization as urgent requests. Other federal regulations generally base these terms on whether the standard timeframe could seriously jeopardize an enrollee’s life, health, or ability to regain maximum function. In 2025, the year for which prior authorization metrics are reported, insurers were required to send a determination for standard requests within 14 calendar days for Medicare Advantage and Medicaid managed care and within 15 days for the ACA Marketplace. Determinations for expedited requests had to be sent within 72 hours for insurers in all three markets.
The 2024 regulation introduced new prior authorization reporting requirements for some business segments and expanded them for others.
- For Medicare Advantage, insurers have been required to report information about the use of prior authorization – including the number of requests, denials, and appeals – for several years, with data available to researchers for 2019 through 2024. Data on the share of prior authorizations approved, denied, and approved upon appeal are largely duplicative of the information Medicare Advantage insurers already report. The regulation adds new requirements to provide information on response times and to report metrics separately for standard and expedited requests.
- For Medicaid and the ACA FFM, uniform federal reporting requirements for prior authorization are new, though an existing patchwork of state laws and regulations has required some insurers to report certain prior authorization data at the state level.
Data collected for this analysis represent the largest insurers in each business segment — those with at least 2.5% market share in each of their respective markets: Medicare Advantage, Medicaid managed care, and the ACA FFM. In total, this analysis includes data from 14 unique insurers, representing 25 million Medicare Advantage enrollees (69% of all enrollment), more than 35 million Medicaid managed care organization (MCO) enrollees (54% of all enrollment), and nearly 11 million enrollees in the ACA FFM (hereafter referred to as the ACA Marketplace for simplicity), which included 28 states in 2025 (74% of all enrollment in FFM states). KFF weighted the data by enrollment within each market segment.
This analysis includes the share of standard and expedited prior authorization requests that were approved and denied, the share of standard prior authorization requests that were approved after appeal, and the median response times for standard and expedited prior authorization requests. We do not report the share of prior authorization requests approved after extension because some insurers reported the data only for standard requests, while others reported data separately for standard and expedited. Optional metrics are not included because they were not consistently reported by insurers.
Approval and Denial Rates
Across market segments, insurers denied between 12% and 18% of standard prior authorization requests in 2025. On average, 12% of standard prior authorization requests and 10% of expedited prior authorization requests were denied in Medicare Advantage; 14% of standard requests and 12% of expedited requests were denied in Medicaid managed care; and 18% of standard prior authorization requests and 16% of expedited prior authorization requests were denied in the ACA Marketplace (Figure 1). Across all markets, the share of standard prior authorization requests that were denied was similar to or slightly higher than the share of expedited prior authorization requests that were denied.
Figure 1
Prior authorization denial rates varied widely across the largest insurers (Figure 2).
Medicare Advantage: Among the six Medicare Advantage insurers examined, the share of standard prior authorization requests that were denied ranged from 5% (Elevance) to 17% (UnitedHealth Group), and the share of expedited requests that were denied ranged from 3% (Elevance) to 13% (Centene). UnitedHealth Group, Centene, Kaiser Permanente, and Elevance all had somewhat higher denial rates for standard requests than expedited requests, while CVS and Humana had higher denial rates for expedited requests than standard requests. These are similar to the overall denial rates found in a previous KFF analysis across Medicare Advantage insurers.
Medicaid Managed Care: Among the eight Medicaid managed care insurers examined, the share of standardprior authorization requests that were denied ranged from 2% (L.A. Care Health Plan) to 23% (Independence Health Group). For expedited requests, denial rates ranged from 4% (L.A. Care Health Plan) to 21% (CareSource). Three insurers (Centene, Independence Health Group, and UnitedHealth Group) reported higher denial rates for standard requests compared to expedited requests, while three insurers (CVS Health, CareSource, and L.A. Care Health Plan) reported slightly higher denial rates for expedited requests.
ACA Marketplace: Among the eight ACA Marketplace insurers included in this analysis, the share of standard prior authorization requests that were denied ranged from an average of 3% (GuideWell) to 25% (Centene). Denial rates for expedited requests ranged from 3% (GuideWell) to 23% (Centene). Four insurers (Centene, UnitedHealth Group, Blue Cross and Blue Shield of North Carolina, and Molina) reported higher denial rates for standard requests compared to expedited requests, while two insurers (Elevance and Health Care Service Corporation) reported higher denial rates for expedited requests. The remaining two insurers (Oscar and GuideWell) in this analysis had virtually the same rates of denials for both standard and expedited requests.
Market segments inherently have many differences, and the share of prior authorization requests denied also varied for the same insurer participating in multiple markets. For example, UnitedHealth denied 17% of standard requests in Medicare Advantage, 11% in Medicaid managed care, and 21% in the ACA Marketplace.
Figure 2
Appeals Data
Insurers overturned a considerable share of denials upon appeal, with variation by market. Although enrollees or their providers can appeal denied prior authorization requests, research shows that denials are rarely appealed in Medicare Advantage, Medicaid MCOs, or the ACA Marketplace. However, the prior authorization data demonstrate that when denials are appealed, a considerable share are overturned.
The share of standard prior authorization requests initially denied that were then overturned upon appeal (referred to in the CMS template as “Requests Approved After Appeal”) was 67% for Medicare Advantage, 47% for Medicaid managed care, and 43% in the ACA Marketplace (Figure 3). We do not present appeals data for expedited requests because that metric is optional, and most insurers did not provide this information. High overturn rates could raise questions about whether the initial request should have been approved or could indicate that the initial request was missing the required documentation to justify the service. Either way, the appeals process can be complicated and time-consuming for providers and patients.
In Medicare Advantage, if the plan upholds its original denial, the case is automatically sent to an independent review entity. In contrast, there is no automatic external medical review of upheld denials in Medicaid managed care and the ACA Marketplace. HHS OIG has suggested that the presence of automatic, independent review could incentivize Medicare Advantage plans to closely review their denials at the first level of appeal and may help explain higher appeal overturn rates in Medicare Advantage compared to Medicaid managed care and the ACA Marketplace.
Appealed prior authorization denials were overturned more often by some large insurers than others (Figure 4).
Medicare Advantage: Across the six largest Medicare Advantage insurers, the share of denied standard prior authorization requests that were approved varied substantially. Denials were overturned upon appeal more than 90% of the time by Centene, while Kaiser Permanente overturned denials upon appeal 40% of the time.
Medicaid Managed Care: Among the Medicaid managed care insurers examined, UnitedHealth Group overturned 81% of denials upon appeal. The remaining insurers overturned between 22%(CVS)and 48%(Molina)of denials upon appeal. (One Medicaid managed care insurer included in this analysis (L.A. Care Health Plan) did not report overturned prior authorization denials as a percentage of standard prior authorization requests that were appealed; therefore, its appeals data are not included here.)
ACA Marketplace: On average, Health Care Service Corporation overturned just 16% of denials upon appeal, while Centene overturned just over half (54%) of denials upon appeal. Six of the eight large insurers reported overturning denials upon appeal less than half the time.
Figure 4
Median Response Times
Median response times for prior authorization determinations were about 1 day for standard requests, with slightly more variation for expedited requests (Figure 5).
The median time between the submission of a prior authorization request and the determination by the insurer, or response time, for standard requests was about 1 day for Medicare Advantage, Medicaid managed care, and the ACA Marketplace (0.9 days or just under 22 hours), substantially less than the federally required maximum time permitted for standard requests. The median response time for expedited requests was about half a day (0.4 days or just under 10 hours) for Medicare Advantage, just under 1 day (0.8 days or approximately 19 hours) for Medicaid managed care, and 1 day for the ACA Marketplace. Federal regulations in 2025 required insurers to send a determination for standard requests within 14 calendar days for Medicare Advantage and Medicaid managed care and within 15 days for the ACA Marketplace. Determinations for expedited requests had to be sent within 72 hours for insurers in all three markets.
Median response times likely reflect (at least in part) the increasing use of technology in the prior authorization process, such as artificial intelligence and electronic prior authorization systems. Still, nearly one-quarter of insured adults reported in a July 2025 KFF poll that their health insurance company had delayed their ability to get a requested health care service, treatment, or medication in the past two years. And other research and media reports demonstrate that some patients experience much longer response times, sometimes with serious health consequences. In addition to the 2024 regulation’s provisions aimed at streamlining and automating the prior authorization process, in June 2025, a group of health insurers voluntarily pledged to expand real-time responses for prior authorization approvals by 2027.
Median response times for prior authorization determinations varied somewhat among large insurers (Figure 6).
Medicare Advantage: The median response time for standard requests varied from less than 1 day (CVS, Humana, and Kaiser Permanente) to 2 days (Centene). Across the six insurers examined, the response times for expedited requests were similar or slightly shorter than the response times for standard requests.
Medicaid Managed Care: The median response time for standard prior authorization requests varied from 1 day (Centene, Elevance, and Molina) to 4 days (CareSource). Elevance had the same median response time for standard and expedited requests, while the other insurers reported shorter response times for expedited requests.
ACA Marketplace: Among the eight large insurers included in this analysis, median response times for standard requests ranged from less than 1 day (UnitedHealth Group, GuideWell, and Health Care Service Corporation) to 4 days (Molina). All but one insurer reported similar or shorter median response times for expedited requests than standard requests.
Figure 6
Challenges for Consumers Accessing and Interpreting Prior Authorization Data
Uniform federal reporting requirements represent a step toward better understanding insurer prior authorization metrics across insurance markets. While the data provide new insights, particularly for Medicaid managed care and the ACA Marketplace insurers, gaps remain. Although a target audience of prior authorization reporting is consumers, those who do not have a deep understanding of health insurance terminology and concepts may struggle to interpret these reports. In previous KFF research, one-quarter of insured adults reported difficulty understanding specific terms their health insurer uses. Difficulty locating metrics on insurer websites, an absence of more detailed data, and unclear reporting standards could additionally pose challenges for consumers wishing to use the data directly to compare health insurers, as envisioned in the 2024 regulation. However, intermediaries may aggregate and explain the data to make it more accessible for consumers.
Insurers are not required to report the number of prior authorization requests for each metric (only percentages), which limits the ability to make useful comparisons and gauge the scale of requests, denials, and approvals behind reported percentages. For instance, a low denial rate could translate into a large number of denials if the insurer received a substantial number of prior authorization requests. Conversely, a high denial rate might be seen with a relatively low number of prior authorization requests if many of those requests were denied (which could indicate the prior authorization process is better tailored, rather than a concerning number of denials). In a previous KFF analysis of the use of prior authorization in Medicare Advantage, for example, the number of prior authorization determinations per enrollee was inversely related to the share of requests that were denied (i.e., insurers with more prior authorization requests denied a smaller share of the requests than those with fewer requests). As a result, the absolute number of denied prior authorization requests per enrollee was similar across insurers with different denial rates.
Numeric counts would provide more context for understanding whether an apparently high or low denial rate reflects a meaningful volume of prior authorization requests. Additionally, they are also necessary to distinguish a true zero from missing data or inapplicable statistics. For example, the “Approved upon appeal” metric does not include the number of appeals an insurer received. Insurers that report 0% of appeals were approved are not required to indicate whether they received no appeals or that none of the appeals were approved. Furthermore, insurers were not required to report the appeal outcome by service or the reason(s) for the decision, making it difficult to interpret differences across and within markets.
Making comparisons between insurers also requires an understanding of policy nuances. An insurer might have a high prior authorization approval rate because there are many services requiring prior authorization that are almost always approved. Some insurers exempt providers from at least some prior authorization requirements if they consistently have a high prior authorization approval rate (e.g., 90%), known as “gold card” programs. These programs can further complicate comparisons, as the approval rate no longer reflects the entirety of the procedures that might otherwise have required prior authorization. Insurers that rely heavily on gold
