Building a network for ACO REACH.

Teams that have built Medicare Advantage networks and then turn to ACO REACH often make the mistake of applying the MA framework to a fundamentally different model. ACO REACH (Accountable Care Organization Realizing Equity, Access, and Community Health) — formerly the Global and Professional Direct Contracting (GPDC) model — operates through CMMI as a value-based care model, not a health plan model. The mechanics are different in ways that matter significantly for how you build and manage the provider organization.

Attribution, not enrollment

The most fundamental difference between ACO REACH and Medicare Advantage is how beneficiaries are connected to the entity. In MA, members affirmatively enroll — they choose the plan and the plan knows who they are before they seek care. In ACO REACH, beneficiaries are attributed — CMS assigns beneficiaries to the ACO based on where they have historically received primary care, without any action on the beneficiary's part.

This has major implications for network building. In MA, you build a network and then attract members into it. In ACO REACH, you build an organization around providers who already have existing patient panels, and the patients those providers already see become your attributed beneficiary population. The starting point is the provider panel, not the geographic footprint.

Who is in your provider organization determines who gets attributed. If your ACO REACH entity includes primary care providers in specific ZIP codes, the traditional Medicare beneficiaries who are receiving primary care at those practices will be attributed to your organization. The quality and total cost of care for those attributed beneficiaries is what your CMMI benchmark will be evaluated against.

Provider alignment agreements vs. traditional contracts

ACO REACH entities sign participating provider agreements with the providers in their network. These are not the same as the payer-provider contracts used in MA. The ACO REACH agreement describes how the entity will share savings (or losses) with participating providers, what care management obligations the providers agree to, what data reporting requirements apply, and what quality metrics providers are responsible for.

Recruiting providers into an ACO REACH entity requires a different conversation than recruiting them into an insurance network. You are not offering a fee schedule — you are offering an upside in shared savings, with accompanying requirements around care management participation, data reporting, and quality performance. Providers who are interested in value-based care arrangements and have the infrastructure to participate in quality reporting are candidates. Providers who want a simple fee-for-service relationship are not.

The primary care foundation

ACO REACH performance lives and dies with primary care. Attribution happens through primary care relationships. The care management activities that drive quality improvement are led by primary care. The total cost of care reductions that generate shared savings are largely achieved through better primary care management of high-cost patients.

Building an ACO REACH entity without a strong primary care foundation is not a viable path. Specialist-heavy organizations can participate in ACO REACH, but the attributable beneficiary population will be small and the performance management levers will be limited.

When we think about network building for ACO REACH, we start with the primary care question: who are the PCPs who are already caring for traditional Medicare beneficiaries in your target geography, and which of them have the interest and infrastructure to participate in a value-based model? That list is the foundation of the entity.

In ACO REACH, you don't build a network and then fill it with patients. You find the providers who already have the patients, and build an organization around them.

CMMI requirements and application

CMMI runs a competitive application process for ACO REACH participation. Organizations that want to enter the model need to demonstrate: a minimum attributed beneficiary population target, adequate financial infrastructure (including the ability to carry downside risk under the professional or global track), governance arrangements that include beneficiary representation, and a health equity plan.

The application process is detailed and requires significant preparation. CMMI provides application guidance and participates in applicant office hours, but the application itself requires specific information about your provider network, your care management model, and your financial projections. Organizations that have built ACO REACH applications with insufficient provider detail or unrealistic beneficiary attribution projections have been declined.

Start the application preparation at least six months before the application deadline. The provider alignment work, the financial modeling, and the governance structure all need to be substantially in place before you can complete a credible application.