Crimson Labs

The strategy many ACOs call the secret to MSSP success

Earlier this week, I met with the head of population health at a health system participating in the Medicare Shared Savings Program. During the course of our conversation, he explained that his organization’s primary strategy for succeeding under the program is reducing network leakage. This is a commonly held point-of-view among many of the accountable care organization (ACO) executives I’ve talked to, so I wanted to explain the reasoning behind it—as well as ways to go about it.

The benefits of patient retention

There are three major benefits to keeping a patient’s care within the ACO.

1. Most ACOs have invested in technology to support information sharing across providers, so care quality is likely to improve from enhanced coordination among doctors. Additionally, most MSSP participants have launched some type of care management program. Keeping patients in the ACO makes it easier for care managers to track a patient and identify gaps in care, further elevating quality.

2. Fee-for-service payments still underpin the shared savings model. The savings come from reductions in admissions, ED visits, and other services. Reducing leakage, and thus increasing the share of services provided by the ACO, can offset some of the revenue loss from utilization declines.

3. The final benefit is simplifying the group practice reporting process. Medicare ACOs must submit clinical data to CMS in order to calculate 22 quality metrics that help determine bonus payouts. The data collection process is onerous to begin with and made worse when relevant patient documentation is housed outside the ACO.

The challenges of keeping care within the ACO

Keeping patient care within the network means ACO leaders need to tackle a few longstanding practices. Many network administrators falsely assume that simply bringing physicians together under the ACO umbrella will be enough to keep referrals within the ACO network.

Personal relationships, however, remain the most common driver of physician-to-physician referrals. And it’s not just the relationships between doctors that matter. A doctor may suggest an in-network referral, but physician office staff responsible for following through on the order have their own processes and relationships that may result in the patient being referred outside the ACO network.

Ways to identify leakage sources

Solving the leakage challenge requires extensive provider and staff education, as well as process improvement. Leveraging Medicare claims data and Crimson analytics, we have helped ACOs prioritize the physicians and practices most in need of support. For example, one Crimson member asked us to determine how much money was spent at inpatient facilities unaffiliated with the ACO and which primary care physicians’ patients contributed most to that leakage.

Based on the table below, it would make sense for the ACO to prioritize outreach to the PCPs with the highest percentage of non-ACO care in order to identify and address any root causes. For example, the ACO may discover that a physician is referring patients to a non-ACO provider because of quality, access, or location issues. The ACO could use that information to improve quality within the network or address patient access issues, and thereby keep more referrals within the network.


Recognizing that primary care doctors aren’t responsible for all admissions, we can identify specialist leakage as well. Crimson uses an episode grouper to measure the total cost of treating a specific condition and attribute those episodes to the relevant physician.

For example, a knee replacement episode would include the inpatient stay, physical therapy, follow-up office visits, and prescription cost of pain medications. We can use this information to determine the percentage of that episode provided by non-ACO providers. The table below highlights one such analysis for an orthopedic surgeon.


Since most ACOs include hundreds of primary care physicians and specialists, they must leverage data to identify key drivers of network leakage and to prioritize outreach. This allows them to target the doctors and practices with the greatest opportunity to redirect cases in-network and improve patients’ overall quality of care—a win-win for patients and providers.

See All the Lessons We Learned from the Early ACOs

In a recent webconference, we shared the lessons we learned from working with the early Medicare ACOs. You can download the presentation and share it with your staff, and you can also catch up with the on-demand recording. Check it out »