An algorithm is now standing between some Medicare patients and the procedures their doctors have recommended. In 2026, the Centers for Medicare and Medicaid Services rolled out the Wasteful and Inappropriate Service Reduction model, known as WISeR, a pilot program running in six states that uses artificial intelligence to screen certain traditional Medicare claims for medical necessity before approving them, a system set to run through December 2031.
What WISeR Actually Does
Traditional, fee-for-service Medicare has historically not required prior authorization for most procedures the way private Medicare Advantage plans do. WISeR changes that for a defined set of services in the pilot states, routing claims through AI models that flag items deemed potentially wasteful or medically unnecessary before a human reviewer signs off on a denial. CMS Administrator Mehmet Oz has framed the program as a way to root out billions of dollars in low-value or inappropriate care without disrupting treatment that patients genuinely need, and the initiative has been championed as part of the current administration’s broader push to curb federal health spending.
The Track Record That Has Doctors Nervous
Physicians’ anxiety about AI-driven denials did not start with WISeR. A 2025 American Medical Association survey found that 61 percent of doctors already worried that AI use by health plans was increasing prior authorization denials, and Medicare Advantage, the privately administered alternative to traditional Medicare that already leans heavily on algorithmic review, has generated a wave of scrutiny to match. Roughly 81 percent of Medicare Advantage denials that were formally appealed in 2024 ended up overturned, and government audits from 2022 found that more than one in ten Medicare Advantage denials occurred despite the claim meeting Medicare’s own coverage rules, according to data compiled by researchers tracking the issue. Among adults with private insurance more broadly, about one in five reported a coverage denial in 2025, and 41 percent of those who experienced a denial said it delayed their care.
The Incentive Problem at the Center of the Debate
Critics of WISeR point to how the private vendors CMS has contracted to run the AI screening are compensated: several arrangements tie vendor revenue to the dollar value of claims averted, a structure that skeptics argue creates a built-in financial incentive to flag more claims for denial rather than fewer. CMS has said human clinical reviewers remain part of the final denial decision, but transparency about how the underlying models actually reach their risk scores has been a recurring complaint from physician groups, who say they cannot meaningfully appeal a decision when they cannot see the reasoning behind it.
Early Signs From the Numbers
Data tracked between June 2025 and April 2026 showed an 11 percent decline in prior authorization requests overall, a trend the program’s supporters point to as evidence that AI screening is reducing unnecessary paperwork and low-value care requests before they are even submitted. Whether that decline reflects genuinely wasteful services being filtered out earlier, or providers and patients simply giving up on requests they expect will be denied, is exactly the question researchers studying the program say they cannot yet answer with the data available.
A Fight Playing Out State by State
Frustration with algorithmic denials has already spilled into state legislatures. Lawmakers in Minnesota and elsewhere have introduced bills to ban AI-driven denials of health insurance prior authorization requests outright, and several states passed laws in 2026 specifically regulating how AI can be used in coverage decisions. Insurers, for their part, made a voluntary pledge in 2025 to ensure a human medical professional reviews any denial involving a clinical judgment call, though patient advocates note a voluntary pledge carries none of the enforcement weight of the state laws now working their way through legislatures.
What to Watch as the Pilot Continues
With WISeR running through 2031, the six pilot states effectively become a multi-year experiment testing whether AI-screened prior authorization can cut genuine waste in traditional Medicare without recreating the denial disputes that have plagued Medicare Advantage. CMS has not detailed a public timetable for evaluating whether to expand the model nationally, but the outcome patients, physicians and state legislators will be watching most closely is simple: does the rate of overturned appeals in these six states start looking like Medicare Advantage’s, or does it stay meaningfully lower.
