Adequate access to primary care is not universally achieved in many countries, including the United States, particularly for vulnerable populations.  In this paper we use multiple years of the U.S.-based Community Tracking Survey to examine whether physician compensation that includes a bonus payment influences the likelihood that a practice takes new patients from a variety of different types of insurance. Specifically we examine the role different bonus pay mechanisms play in determining whether or not physicians are more likely to accept patients who have private insurance, Medicare, or Medicaid. Since physician reimbursement varies across these different types of payors, the incentive for accepting new patients may differ when bonuses are revenue-based, as opposed to patient satisfaction- or quality-based.  Thus, the presence of particular forms of bonus arrangements may interact with the incentives inherent in payor reimbursement to create varying incentives to provide access for patients.  There is a significant trend toward larger numbers of physicians choosing salaried employment rather than equity partnerships. If physicians’ financial arrangement affect their willingness to accept Medicaid or Medicare patients, implementing the Medicaid expansions envisioned under the Affordable Care Act may prove problematic.

Additionally, in the United States these different types of insurance mechanisms cover populations with different levels of vulnerability.  Medicare (elderly and disabled individuals) and Medicaid (low income households) enrollees commonly have lower ability to pay any cost sharing associated with care, are more likely to have multiple comorbidities (and so be more costly to treat), and may be more sensitive to poor access.  Further, these two insurers also generally reimburse less generously than private payors.  Thus, if lower reimbursements interact with bonus-based compensation mechanisms to discourage physician practices from accepting new patients, lower income / highly vulnerable populations may be at even greater risk than generally appreciated.

The Community Tracking Survey supports analyses to test the likelihood that physicians will accept new private insurance, Medicare, or Medicaid enrollees given a variety of factors that affect physicians’ total compensation.  Our analysis also directly tests how the financial incentives of employees differ from physicians with ownership stakes in the practice. We find that the compensation structure of physicians is a statistically and economically significant predictor for the types of new patients that practices accept, and that this effect depends upon the equity position (employee vs. partner) of the surveyed physician. These findings have important implications for both policy makers and private health care systems.