Editor’s Note: In a recent issue of Annals of Internal Medicine, the premier internal medicine journal published by the American College of Physicians, Manatt Health coauthored a new article calling for raising the rigor and transparency around how attribution models are chosen. The article, summarized below, examines concerns with current models, as well as details approaches for moving forward.


To improve coordination and integration of care, the U.S. Department of Health & Human Services has set an ambitious goal of tying more than 90% of Medicare payments to quality by 2018 and shifting more than half of payments to alternative payment models, such as accountable care organizations (ACOs) and bundled payments. Unfortunately, in this rapid shift to new payment models, the issue of attribution is not receiving sufficient attention.

What Are Attribution Models?

Patients receive care from a broad range of providers, including hospitals, physicians and nurses. Attribution models are sets of rules used to determine which providers (or groups of providers) have responsibility for a patient’s care, from a quality, cost or payment perspective. The models vary widely and are often complex.

Concerns With Current Models     

There are several major concerns with current attribution models:

  • Methods for determining attribution vary widely and are inconsistent.
  • There is a lack of transparency around how a patient’s care is attributed and often an inability to clarify or appeal the model.
  • Providers worry that they will be held responsible for care over which they have little control. For example, an attribution model may assign responsibility for a woman’s breast cancer screening to the physician who saw the patient for the most visits in a year—but that physician might be a dermatologist who expects the patient’s primary care physician to be responsible for breast cancer screening.

The limited literature on the topic has shown that attribution models matter, often significantly. In one study, more than half of physicians were assigned to a different cost category (high, average or low) if an attribution model other than the default was used.   

How to Move Forward

The National Quality Forum tackled the concerns around current attribution models in a multistakeholder committee. Though it is not currently feasible to select a single, ideal attribution model for use across all applications, there are several ways that the clinical and policy communities can move forward:

  • More attention must be paid to attribution, given its proven importance.
  • Health plans and other payers can use the National Quality Forum’s selection guide, “Attribution: Principles and Approaches,” to help them determine the right attribution model.
  • New ways of attributing care must be considered, such as using data from electronic health records.
  • Greater transparency and mechanisms for appealing inappropriate attribution are needed.
  • Attributed providers (whether individual physicians or organizations) must be able to influence the outcomes for which they are held accountable. 


The issue of attribution clearly will become more and more important, as the United States moves forward with alternative payment models and increased performance measurement. We need to raise the bar on the rigor and transparency around how attribution models are chosen.