The Effect of Different Attribution Rules on Individual Physician Cost Profiles

When a patient receives care from multiple doctors, the rule used to assign primary responsibility to one doctor often determines their cost profile.

Health plan and government analysts compare physicians based on their cost profiles, (i.e., high cost or low cost). When a patient sees multiple physicians, analysts use attribution rules to assign responsibility to a single physician. This study tested whether using different attribution rules changed physicians’ cost profiles.

The authors constructed their physician cost profiles using methods similar to those used by health plans. There were 12 attribution rules that fell into two basic types: patient-based rules assigned all patient costs to one or more physicians; episode-based rules assigned costs separately for each of the patient’s conditions. The study analyzed all claims from 2004 to 2005, submitted to four health plans in Massachusetts (roughly 14,000 physicians and 1 million patients).

Key Findings:

  • Using a different attribution rule placed 17 percent to 61 percent of physicians in a different cost profile.
  • Patient-based and multiple physician-based rules generated the most variance in cost profiles.

This article presents a study that analyzed how rules used to assign primary responsibility for patient care affect a physician’s cost profile.