Many assume that healthcare savings come from doing less: fewer tests, fewer referrals, and fewer interventions. Accountable Care Organizations do not operate that way. ACOs reduce costs by delivering the right care at the right time, and when they spend less than the Medicare benchmark while meeting quality requirements, they receive a share of the savings.
That is the model in simple terms. The next question is how an ACO achieves this. What actions within the organization improve both cost and quality performance?
The Spending Benchmark Is Everything
The entire shared savings model revolves around one number: the benchmark. CMS estimates how much Medicare would spend on an ACO’s patient population based on historical data. If the ACO spends less than that amount and meets quality thresholds, it receives a percentage of the savings.
Spend $46M on a $50M benchmark? That $4M gap represents savings, and the ACO may retain a portion based on program rules.
How ACOs Stay Under the Benchmark
Staying below the benchmark is not about reducing necessary care. It’s about being precise. ACOs focus on:
- Identifying high-risk patients early before manageable conditions lead to hospitalization.
- Closing care gaps, improving medication adherence, and addressing chronic conditions help reduce downstream costs.
- Structured post-discharge follow-up helps reduce avoidable readmissions.
- Accurate HCC capture and proper documentation help ensure the benchmark reflects true patient complexity.
Risk Stratification: The Engine Behind Proactive Care
Accountable Care Organizations can’t manage every patient the same way. Resources are finite, and not every patient carries the same risk. Risk stratification addresses this by segmenting the population, so care teams know where to focus.
A well-stratified ACO population typically breaks into three tiers:
- High-risk: Complex chronic conditions, frequent utilization, high probability of avoidable events; these patients need active care management
- Rising-risk: Trending in the wrong direction, but not yet in crisis. Early outreach here prevents escalation
- Low-risk: Stable patients who need routine monitoring and preventive care touchpoints
Without this structure, care managers are reactive. With it, they’re strategic.
The HCC Capture Problem Most ACOs Underestimate
Hierarchical Condition Categories determine how CMS sets benchmarks and risk scores. A patient with five documented conditions is benchmarked differently than the same patient with only two. If chronic conditions go uncaptured, the ACO’s benchmark is set artificially low, making savings mathematically harder to achieve.
Accurate HCC capture isn’t upcoding. It’s telling the full clinical story.
Data Is What Separates Good Intentions From Actual Results
An ACO without real-time data visibility lacks the insight needed for timely decisions. Care teams need to know which patients are attributed, what their recent utilization patterns look like, where gaps exist, and how current spending tracks against the benchmark, not in January after CMS reconciliation, but throughout the year.
This is where a digital health platform becomes essential. Aggregating claims, clinical, lab, and pharmacy data into a single actionable view enables providers and care managers to act at the point of care rather than relying on delayed reports.
ACO Risk Tracks Matching Risk Appetite to Organizational Readiness
ACOs operate under different CMS models with different financial structures:
| Model | Upside | Downside Risk |
| MSSP Basic | Shared savings only | None |
| MSSP Enhanced | Higher savings rate | Shared losses |
| ACO REACH | Capitation options | Full risk possible |
| CMS LEAD Model (2027) | Stable 10-year benchmarks | Long-term risk |
Starting January 1, 2027, the CMS LEAD Model, which replaces ACO REACH, has a ten-year performance period. It introduces more predictable benchmarks and risk structures, which benefit organizations focused on long-term sustainability rather than year-to-year performance.
What Consistently High-Performing ACOs Do Differently
The data and the model are available to every ACO. What separates those that generate real savings from those that don’t comes down to execution:
- They track benchmark performance mid-year, not after the fact
- They have proactive outreach built into workflows, not bolted on
- Providers are engaged at the point of care with real-time patient context
- Risk documentation is treated as a clinical priority, not a billing afterthought
Conclusion
Accountable Care Organizations reduce costs by improving care coordination rather than limiting services. They improve outcomes while controlling costs through proactive care management, accurate documentation, and real-time data. As CMS introduces models like the LEAD Model to support long-term value-based care, organizations with strong infrastructure will be better positioned to succeed. Persivia CareSpace® is a predictive analytics platform that supports ACOs with risk stratification, care management, and real-time insights to address care gaps and stay aligned with benchmarks.
