On October 20, 2026, the Centers for Medicare and Medicaid Services published a proposed rule in the Federal Register that would require Medicare Advantage plans to maintain provider directories that meet specific accuracy standards, conduct regular verification checks, and publish accuracy scores the public can compare. The comment period closes December 15, 2026. Nothing in the proposal is in effect yet.

If you or someone you care for is enrolled in a Medicare Advantage plan, this matters for a concrete reason: the list of doctors a plan shows as in your network may not reflect who is actually available to see you.

How inaccurate are these directories?

The available evidence is serious, though none of it can be read as the current national rate for every plan or specialty.

In 2018, CMS itself conducted what it called a Round 3 audit of Medicare Advantage provider directories, reviewing 5,602 providers across 10,504 listed locations. Auditors found that 48.74 percent of those locations had at least one inaccuracy, and 41.75 percent had an error they judged likely to prevent access to care. Providers should not have been listed at 33 percent of locations. There were 690 wrong or disconnected phone numbers, 364 incorrect addresses, and 221 listings that incorrectly stated the provider was accepting new patients. CMS stated its conclusion simply in that report: "Because MAO members rely on provider directories to locate in-network providers, accurate information is critical."

The problem has continued to draw attention in more recent years. In October 2025, the HHS Office of Inspector General published a report on behavioral-health networks in selected Medicare Advantage and Medicaid managed care plans. In more than half of the Medicare Advantage plans reviewed, at least one-third of listed behavioral-health providers showed no claims activity and were classified as inactive. The OIG noted that providers who appear in a directory but are not actually seeing patients can make a network appear larger than it is.

Senate Finance Committee majority staff documented a similar pattern through a smaller study in May 2023, sending testers to book appointments using 120 mental-health listings across 12 Medicare Advantage plans in six states. One-third of the listings were inaccurate, non-working, or produced no response. Appointments were actually made 18 percent of the time. Senator Ron Wyden, describing what patients encounter when they follow these listings, put it this way in his prepared remarks: "The last thing they need is a symphony of 'please hold' music, non-working numbers, and rejection."

What the proposed rule would require

The October 20 proposal implements the REAL Health Providers Act, legislation Congress already enacted. The proposed requirements would apply beginning with plan year 2028.

If finalized as written, the rule would require Medicare Advantage plans to verify provider information at least every 90 days, with some facility types subject to no less than annual schedules. Plans would be required to flag information they cannot verify and to remove a provider from the directory within five business days of determining that provider is no longer in network. Directories would have to include specific fields: name, specialty, contact information, primary office or facility address, whether the provider is accepting new patients, disability accommodations, cultural and linguistic capabilities, and telehealth capabilities.

Plans would also conduct annual sample-based analyses of their own directory accuracy and submit scores to CMS. Beginning in 2029, CMS would publish those plan-level scores in machine-readable format, and plans would be required to display them prominently.

The proposed rule includes a cost-sharing protection as well. If an enrollee makes an appointment on a date when the directory lists the provider as in-network, then later learns the provider was out of network, the enrollee's out-of-pocket responsibility for a service the plan would otherwise cover would be capped at the lesser of the in-network cost-sharing amount or what would otherwise apply. This protection would begin with plan year 2028, if the rule is finalized.

What this evidence cannot tell us

The 2018 audit and the 2025 OIG report are the most substantial data points in the public record on this question. Both have real limits.

The CMS audit reviewed a sample of providers across 52 Medicare Advantage organizations. It cannot tell you the current error rate for your specific plan, your specialty, or your county. Error rates vary across plans, regions, and provider types, and the audit reflects conditions eight years ago.

The OIG report focused specifically on behavioral-health providers. A provider who shows no recent claims activity is worth flagging, but inactivity in encounter data is not the same as unavailability. A provider might stop billing through a given plan's claims channel and still accept patients under different arrangements.

The Senate Finance study used 120 listings across six states. It captures a pattern that appears consistently across multiple types of investigations, but it is not a national representative sample and cannot be used to estimate what share of all Medicare Advantage listings are unusable today.

No study in the public record establishes a single current national error rate, and none of them can answer whether your specific listing, for your specific plan, at your specific location, is accurate right now.

What this means in practice

If the proposed rule is finalized, and if it survives the comment process and implementation without significant revision, Medicare Advantage directories will function differently starting in 2028. Plans will carry a formal obligation around listings that were verifiably wrong when a patient relied on them. Beginning in 2029, public accuracy scores would give patients and their advocates a way to compare plans on this dimension before enrolling.

That is a meaningful structural shift. The burden of figuring out whether a listing is real has historically fallen almost entirely on the patient and whoever helps them navigate care. A rule that caps cost-sharing when a patient relied on a wrong listing moves some of that burden toward the plan.

Two years is still a long time to wait, and a proposed rule is not a finalized one. The comment period runs through December 15. What the final rule preserves, modifies, or removes from the current proposal is not yet decided.

What you can do now

Until the proposed rule takes effect, the most practical protection for an enrollee or caregiver is documentation.

Before booking an appointment through a directory listing, save the listing itself: take a dated screenshot or print a PDF that shows the plan name, the provider's name, the specialty, the address, and the accepting-new-patients status. That record establishes what you relied on and when.

When you call the provider's office to confirm, ask specifically whether they accept your plan at the location listed in the directory. Many providers contract with a plan under some group or location identifiers but not others. Write down the date, the time, and the name of the person you spoke with.

A question worth asking at every step: does this provider, at this specific location, accept my Medicare Advantage plan, and are they currently taking new patients?

Sources