Framing the Issue:

To measure the quality and cost of care, payers identify which provider is accountable for which patient. It can be a messy process.

Most payers attribute patients to primary care physicians, but a patient with chronic or urgent conditions may see a specialist physician more than a PCP.

PPO patients can move from provider to provider at will.

Most attribution depends on retrospective data, usually from the prior 12 months. But that makes it difficult for physicians to predict and address patient needs in the year ahead.

Nonetheless, some population health experts say attribution data can improve outcomes.

New care delivery and payment models all seem to have the same key elements: a defined population, panels of people for whom health care providers are accountable, and a way to tie measures of quality and cost to those responsible. Unfortunately, it’s not that simple. There are no neatly defined panels of patients tied to specific providers. The dominant form of health plan, the preferred provider organization, generally permits people to seek care from a sizable group of providers and to change their minds at will. In addition, these people may change their addresses or switch insurance carriers, which can confound attempts to define a patient panel for any measurable length of time. But some organization must be responsible for these patients so that provider networks can “more effectively manage the population, and to ensure that everyone is getting the care that’s appropriate to their [respective] condition,” says Michael Simon, principal data scientist with analytics vendor Arcadia Healthcare Solutions.


A process called attribution is intended to resolve that issue. It uses mainly medical claims to identify all the providers that a patient sees and the costs applied to the patient’s illness and wellness, and determines who among a patient’s providers should be accountable for his or her condition and health care expenditures. With its many variables, attribution is neither exact nor simple.

The details of attribution formulas usually are determined by health insurance plans that make value-based assessments part of their contracts, though providers can influence or even assume the task if they are sophisticated enough, says Nathan Gunn, president of the population health division of Valence Health, an analytics and consulting firm.

But no matter how attribution is set up, it has the potential to create physician frustration and resistance, especially if it affects the amount of supplemental payments for patient coordination and management, or if doctors are penalized based on results from other providers a patient may see.

Retrospective vs. prospective attribution

The most accurate way to attribute patients to accountable physicians is to track and measure the behavior of a target population after the end of a reporting period, which is typically one year. Software loaded with attribution logic, usually employed by the payer who is originating a value-based contract, looks at every encounter with the health system and the costs incurred, and it retrospectively assigns a patient to the physician he or she appears to see most often.

Payers generally assume that a person is under the care of a certain primary care physician whom he or she sees during a plan year, even with patients’ freedom to engage specialists for chronic or acute ills or go outside the contracted system, says Christopher Stanley, M.D., vice president for care management at Catholic Health Initiatives, Englewood, Colo. Physicians use that retrospective determination of attributed patients to inform their actions in the coming year. But, unless there are ways to update and inform doctors on patients’ movements, “[they] really don’t know what that patient is going to do over the next 12 months,” he says. The frustration for physicians is that they won’t know which patients they are responsible for until the end of the year. “By then, it’s too late to reach out to them.”

The alternative is to make the process prospective, using a similar attribution process as a basis for accountability going forward instead of looking back. Attributed patients are known to their providers, who can use the care and cost data that come in during the year to respond to problems immediately, says Dana Gelb Safran, senior vice president for performance measurement and improvement for Blue Cross Blue Shield of Massachusetts. “If you’re going to ask a provider to be accountable for a population, it’s good if they know who they’re accountable for, so that they can be actually managing care in a way that will deliver good quality and affordability results,” she says.

When providers have no sense of who is going to be officially responsible for their patients nor a way to get at that determination, Simon says, “that leaves a sense of powerlessness in the face of an incentive contract.”

Nevertheless, the multiple pilot projects emanating from the Affordable Care Act, such as the Pioneer Accountable Care Organization model and the Medicare Shared Savings Program, mean momentum is behind retrospective attribution. The Centers for Medicare & Medicaid Services recently allowed some measure of patient recruitment into a particular ACO’s attributed population to provide some predictability, but the basis for deciding which Medicare beneficiaries are in or out of an ACO is still mainly tied to the previous year.

Narrowing down the provider

Another variable in the attribution process is the type of practitioner ultimately deemed the main influence on care services and costs. Chronic illness care calls for a primary care provider who has a big say in the treatment plans of patients, even if they more often go to a cardiologist or pulmonologist. But specialists sometimes call the shots, especially in an episode of care requiring a procedure or other intensive intervention.

Clinically integrated networks already are running with educated decisions on the formulation of their attributed population. “Really, truly understanding patient behavior, and starting with primary care” is essential in the attribution process, says Daniel Edelstein, director of Northwest Alliance ACO, a Minneapolis-area network.

Making the decision on the proper primary care physician involves looking for certain patient activities. Insurers first look for “well visits,” Safran says. “Typically a patient does not schedule a well visit with somebody other than their primary care doctor.” Next, they look for urgent care visits, the sources of prescriptions, and then other kinds of PCP visits, such as for a blood draw.

“You’re using your claims data to tell you, based on the number and type of encounters, who appears to be the doctor for this patient, and then what system that doctor is in,” she says. “You take all the patients assigned to doctors in that system and that becomes the system’s population.”

As approaches to population health become more prevalent, the impact of attribution is increasingly clear. “If we’re really trying to move toward accountable care and managing populations, it’s all about what population is being served, and attribution clearly defines that,” Edelstein says. “Off that population served, and off the value-based arrangements that are contractually made with the plans, we can quite easily measure total cost of care and put a real accountability on affordability.”

With the data derived from attributing patients to their responsible doctors, Northwest Alliance ACO and its physicians are better equipped to identify opportunities to improve care quality and affordability, Edelstein says.

“It clearly has people asking the right questions,” he says. For example, the higher-than-usual use of inpatient mental health services was a concern for the ACO. “So, what are the driving causes of this? Physician practices? Gaps in the care continuum? Lack of integration?” In the past, advocates for the integration of primary and behavioral care had few champions, but the accountability for cost data by attributed provider has made primary care physicians more engaged, Edelstein notes. As a result, the ACO has added “a ton of resources” to mental health, including bringing behavioral health inside primary care clinics.

The onus on primary care physicians also provides momentum for team-based care, including the use of physician assistants and nurse practitioners.

Getting past the disruption

It’s important to accept the imperfections of attribution and move on to what it can achieve for the organization, Stanley advises. “In our approach, we’re trying to lead by saying attribution and similar types of methodologies should not ever be used to blame a physician, blame a patient or negatively look at how care is being provided, but rather should be a mechanism by which we can actually improve the health and well-being of the communities that we serve,” he says. “This type of tool, as long as you understand the limitations and how it will help support your tactics, can be a very, very powerful tool to help improve the health of the population.”

With physicians who feel powerless, Stanley says the key is to turn the questions back to them and say, “Here are our shared goals, here’s the patient-focused approach and our methodology to reach that, and here’s how we’d like to take ownership and accountability for it.”

Once incentives are fully aligned under full risk at a fundamental level, “you don’t have to do all these workarounds, which is what attribution is: workarounds in a fee-for-service world.”

John Morrissey is a freelance writer in Chicago



Executive Corner

The upside of attribution: Physician teamwork

At Northwest Alliance ACO, the primary care focus of attribution has helped to develop teamwork with specialists, says Daniel Edelstein, the network’s director. Frequent meetings are scheduled between primary care physicians and selected specialty groups around achieving health care’s Triple Aim of optimal quality delivered with maximum efficiency and high patient satisfaction with the care experience. Specialists have a vested interest in maintaining good relations because they depend on primary care physicians for referrals.

For the most part, the performance of other specialists burnishes the attributed doctor’s quality metrics, says Dana Gelb Safran, senior vice president for performance measurement and improvement for Blue Cross Blue Shield of Massachusetts. A specialist can only be helping by doing tests that are important to the care of a network’s patient population, which accrues to the primary care physician’s advantage. For a diabetes patient who sees an endocrinologist for relevant screenings, to cite one example, that physician’s contributions will help to keep the patient’s diabetes under control and contribute to a higher quality of life while preventing unnecessary hospital expense, Safran says.