ASM: Selection and Notification Process Explained, An Annual Cycle, Not a One-Time Event

As we await the 2027 ASM participant list, keep in mind ASM selection isn’t a one-time event—it’s a data-driven, multi-year process tied to historical claims and episode volume.

In addition to clinician-level eligibility described below, the Ambulatory Specialty Model (ASM) is mandatory only in selected geographic areas. CMS used a stratified random sampling methodology to identify Core-Based Statistical Areas (CBSAs) and metropolitan divisions from which clinicians are selected for participation. CMS has released the geographic mandatory areas.

The Ambulatory Specialty Model (ASM) uses a prospective, data-driven selection process that relies on historical Medicare claims and episode volume to determine which clinicians are required to participate each year. While participation in the model spans the full ASM test period once selected, performance-year obligations are reassessed annually.

Below is a breakdown of how CMS selects and notifies ASM participants, based directly on the final rule.

Identification of ASM Participants Each Year

For each ASM performance year, CMS identifies clinicians furnishing covered services by applying the ASM participant eligibility criteria using applicable data from two calendar years prior to the performance year.

Importantly:

• Any clinician selected for participation for any year of the model is considered an ASM participant for the remainder of the ASM test period

• However, whether ASM requirements apply in a given year depends on annual eligibility reassessment

CMS makes participant lists public in a form and manner determined by CMS, reinforcing the transparency of the process.

Selection Process for the 2027 ASM Performance Year

Because 2027 is the first ASM performance year, CMS established a two-step selection and notification process.

Step 1: Preliminary Eligibility (CY 2024 Data)

Using calendar year 2024 claims and episode data, CMS identifies clinicians who meet the ASM participant eligibility criteria for:

• 2027 ASM performance year

• 2029 ASM payment year

These clinicians are designated as preliminarily eligible ASM participants, and CMS publicly releases this preliminary list.

Step 2: Final Participant Confirmation (CY 2025 Data)

CMS then confirms eligibility using calendar year 2025 data to ensure clinicians continue to meet the eligibility criteria.

Clinicians confirmed through this process are identified as final ASM participants for:

• 2027 ASM performance year

• 2029 ASM payment year

This final list is also made public by CMS.

Selection and Reassessment Beginning in 2028 and Beyond

Starting with the 2028 ASM performance year (2030 payment year), CMS transitions to an annual reassessment framework.

Annual Reassessment of Existing ASM Participants

For clinicians already identified as ASM participants, CMS:

• Evaluates eligibility using data from two years prior to the upcoming performance year

• Determines whether ASM requirements apply for that specific year

  
  

If an ASM participant does not meet eligibility criteria for an upcoming performance year:

• They are not subject to ASM requirements for that year (including reporting and financial provisions)

• They must participate in MIPS, if otherwise applicable

Despite this, the clinician remains an ASM participant for the duration of the model.

Adding New ASM Participants Each Year

Beginning in 2028, CMS also evaluates clinicians not previously identified as ASM participants.

• CMS applies the same eligibility criteria using two-year lookback data

• Newly eligible clinicians are added as ASM participants for the applicable performance year

• Updated participant lists are published annually

Key Takeaways for Clinicians and Health Systems

• ASM selection is claims- and episode-based, using a two-year lookback

• Selection is publicly reported and reassessed annually

• Participation in the model is longitudinal, but obligations are performance-year specific

• Clinicians may move in and out of ASM reporting requirements, with corresponding shifts between ASM and MIPS

Bottom line: Understanding historical episode volume—and monitoring it continuously—is essential. By the time CMS publishes eligibility lists, the underlying data is already two years old, leaving little room to react without advance planning.