Written and maintained by CASRAI Editorial Board
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For health system revenue cycle directors, population health informaticists, and health economics and outcomes research (HEOR) investigators, the ACO REACH Model (Accountable Care Organization Realizing Equity, Access, and Community Health) represents the Centers for Medicare & Medicaid Services (CMS) Innovation Center’s flagship population-based alternative payment model in Traditional Medicare. Evaluating value based care reimbursement requires comparing how the ACO REACH Model differs structurally from the permanent statutory Medicare Shared Savings Program (MSSP) (shared savings program ACO) and episode-based models such as Bundled Payments for Care Improvement Advanced (BPCI Advanced).
What Is the ACO REACH Model? Statutory Authority, Tracks, and Risk Arrangements
Authorized under Section 1115A of the Social Security Act and launched on January 1, 2023 (redesigning and replacing the Global and Professional Direct Contracting [GPDC] model through December 31, 2026), the ACO REACH Model requires participating organizations to assume two-sided financial risk and prospective capitated cash flow for aligned Traditional Medicare (Fee-for-Service Part A and Part B) beneficiaries.
CMS categorizes ACO REACH participants into three organizational tracks based on beneficiary alignment history and clinical complexity:
- Standard ACOs: Organizations with substantial historical experience serving Traditional Medicare beneficiaries (aligned via historical claims or voluntary beneficiary alignment).
- New Entrant ACOs: Organizations that have not traditionally provided services to a Traditional Medicare Fee-for-Service population, relying primarily on voluntary alignment during initial performance years.
- High Needs Population ACOs: Organizations employing an intensive care-delivery model tailored to medically complex, frail, or dually eligible Medicare-Medicaid beneficiaries with high Hierarchical Condition Category (HCC) risk scores.
Every ACO REACH participant must select one of two two-sided risk-sharing arrangements:
- Professional Risk Arrangement (50% Risk): The ACO bears 50% of shared savings and 50% of shared losses against its performance year benchmark and must participate in Primary Care Capitation (PCC)—a prospective monthly capitated payment equal to 7% of the ACO’s total benchmark cost of care covering primary care services.
- Global Risk Arrangement (100% Risk): The ACO bears 100% of shared savings and 100% of shared losses (subject to risk corridors and a CMS Global discount factor of 2% to 3.5%) and chooses between Primary Care Capitation or Total Care Capitation (TCC), where CMS pays the ACO a prospective monthly capitated amount covering both primary and specialty care services delivered by Participant and Preferred Providers.
Capitation vs. Fee-for-Service (FFS): How Claims and Cash Flow Operate
A foundational technical distinction in capitation vs. fee for service informatics is that capitated Medicare models still require complete encounter claim submission through a medical claims clearinghouse so CMS can track utilization, calculate risk scores, and reconcile total expenditures:
- Traditional Fee-for-Service (FFS) in MSSP: Participating providers submit ASC X12N 837 claims to their Medicare Administrative Contractor (MAC) and receive 100% of the standard Medicare Physician Fee Schedule or Inpatient Prospective Payment System reimbursement per service. Shared savings or losses are settled once annually after the performance year ends.
- Capitated Claim Reductions in ACO REACH: Under Primary Care Capitation or Total Care Capitation, Participating Providers still submit compliant X12 837 claims to CMS, but CMS applies an automated 100% fee reduction (zero-pay adjudication) on capitated services (or a provider-elected 1% to 100% fee reduction for Preferred Providers), while paying the ACO a predictable monthly prospective capitation payment. The ACO then distributes funds to its network providers according to its internal downstream payment arrangements.
ACO REACH Model vs. Shared Savings Program ACO (MSSP) vs. BPCI Advanced
The table below compares the three primary Medicare alternative payment architectures across statutory authority, risk tracks, payment mechanics, governance, and clinical care-delivery waivers:
| Comparison Dimension | ACO REACH Model (CMMI) | Medicare Shared Savings Program (MSSP) | BPCI Advanced (Bundled Payments for Care Improvement) |
|---|---|---|---|
| Statutory Authority & Lifespan | Section 1115A CMS Innovation Center (CMMI) time-limited demonstration model (Performance Years 2023–2026). | Permanent statutory Medicare program under Social Security Act § 1899 (42 CFR Part 425). | Section 1115A CMMI episode-based payment model (transitioning toward mandatory CMS TEAM surgical episode bundles in 2026). |
| Accountability Unit | Total Part A & Part B annual cost of care for aligned Traditional Medicare beneficiaries (Standard, New Entrant, or High Needs tracks). | Total Part A & Part B annual cost of care for at least 5,000 assigned Traditional Medicare beneficiaries. | 90-day clinical episode triggered by a specific inpatient MS-DRG stay or outpatient HCPCS procedure plus 90 days post-discharge. |
| Financial Risk Sharing | Mandatory two-sided risk from Day 1: Professional (50% savings/losses) or Global (100% savings/losses) after risk corridors. | BASIC Track (glide path Levels A–E, starting at one-sided upside risk and progressing to two-sided risk) or ENHANCED Track (up to 75% shared savings). | Two-sided retrospective episode reconciliation against a prospective target price (with a 20% stop-gain / stop-loss cap at the participant level). |
| Cash-Flow Mechanism (Capitation vs. FFS) | Mandatory prospective monthly capitation: Primary Care Capitation (PCC) or Total Care Capitation (TCC) paired with FFS claim fee reductions. | 100% Traditional FFS claims reimbursement throughout the year (plus optional Advance Investment Payments [AIP] for eligible low-revenue new ACOs). | 100% Traditional FFS claims paid to all providers during the 90-day episode, followed by semi-annual net payment reconciliation adjustments (NPRA). |
| Health Equity Benchmark Adjustment | Explicit Health Equity Benchmark Adjustment (HEBA) adding +$30 PMPM for beneficiaries in the top 90th–100th percentile of national Area Deprivation Index (ADI) scores, funded by a -$6 PMPM adjustment on the lowest 50%. | Health Equity Adjusted Quality Performance Score bonus points and regional/prior-savings benchmark adjustments under 42 CFR Part 425. | Peer-group and patient case-mix risk adjustments built into clinical episode target price regression models. |
| Governance Requirements | At least 75% of governing board voting rights must be held by participating providers (unchanged from 75% baseline), plus both a Medicare beneficiary advocate and a consumer advocate in distinct voting roles. | At least 75% of governing body control must be held by ACO participants, plus at least one Medicare beneficiary served by the ACO on the board (42 CFR § 425.106). | Convener or Non-Convener Acute Care Hospital (ACH) or Physician Group Practice (PGP) episode initiator governance. |
| Benefit Enhancements & Clinical Waivers | Broad CMMI waivers: 3-day SNF rule waiver, telehealth place-of-service waiver, post-discharge home visits, nurse practitioner specialty care order waivers, and Part B cost-sharing support for high-value services. | 3-day SNF rule waiver (for two-sided risk tracks), expanded telehealth flexibilities, and Beneficiary Incentive Program (up to $20 per qualifying primary care service). | 3-day SNF rule waiver, post-discharge home visit waiver, and telehealth geographic/originating-site waivers during the 90-day episode. |
How Is the ACO REACH Model Used in Clinical Research and Healthcare Informatics?
In health services research and clinical informatics, the ACO REACH Model introduces three distinct data and operational workflows that intersect with utilization management in healthcare and HIPAA in clinical research governance:
- Claim-Line Feed Ingestion (CCLF Files): CMS transmits monthly Claim and Claim Line Feed (CCLF) files containing complete Part A, Part B, and Part D claims across all care settings for aligned beneficiaries, enabling ACO informatics teams to identify care gaps, high-risk emergency department utilization, and post-acute skilled nursing facility leakage.
- Health Equity Data Collection and Stratification: Participating ACOs must execute a CMS-approved Health Equity Plan and systematically collect and report beneficiary self-reported demographic and social needs data via EHR standards, earning quality score adjustments.
- Clinical Trial Billing Separation: When an ACO REACH or BPCI Advanced beneficiary enrolls in an interventional clinical trial, revenue cycle and research billing teams must ensure routine qualifying trial costs and sponsor-paid items follow clinical trial charge capture and billing reconciliation rules so research-related claims do not distort capitated fee reductions or episode target reconciliations.
Frequently Asked Questions
What is the ACO REACH Model?
The Accountable Care Organization Realizing Equity, Access, and Community Health (ACO REACH) Model is a CMS Innovation Center (CMMI) alternative payment model (operating Performance Years 2023–2026 under Section 1115A of the Social Security Act) that tests two-sided total cost of care risk (50% Professional or 100% Global risk), mandatory prospective capitation (Primary Care Capitation or Total Care Capitation), and a Health Equity Benchmark Adjustment in Traditional Medicare.
How is the ACO REACH Model used in clinical research and healthcare?
Health systems, physician groups, and health services researchers use the ACO REACH Model to evaluate how prospective capitated payments, provider-led governance (at least 75% participating provider board control), Area Deprivation Index (ADI) health equity adjustments, and Medicare Benefit Enhancements (such as 3-day SNF rule waivers and home visit flexibilities) impact population health outcomes and total Medicare Part A and Part B spending.
Sources
- CMS Innovation Center (CMMI) — Accountable Care Organization Realizing Equity, Access, and Community Health (ACO REACH) Model Specifications
- Centers for Medicare & Medicaid Services (CMS) — Medicare Shared Savings Program (MSSP) Regulations (42 CFR Part 425)
- CMS Innovation Center (CMMI) — Bundled Payments for Care Improvement Advanced (BPCI Advanced) Model Overview
