Geographic modifiers adjust Medicare physician payments to reflect the real cost of practicing medicine in different parts of the country. A doctor performing the same procedure in Manhattan and rural Mississippi gets paid different amounts because rent, staff wages, and malpractice insurance vary dramatically by location. These adjustments, formally called Geographic Practice Cost Indices (GPCIs), are built into every payment Medicare makes to physicians under its fee-for-service system.
The Three Components of Geographic Adjustment
Medicare breaks every physician payment into three pieces, and each one gets its own geographic modifier:
- Physician work: the value of a doctor’s time, effort, and skill for a given service. The work GPCI reflects differences in how much physicians earn across regions.
- Practice expense: what it costs to run an office, including staff salaries, rent, supplies, and equipment. This component varies the most between locations because commercial real estate and local labor markets differ widely.
- Malpractice expense: the cost of professional liability insurance, which can swing significantly depending on state tort laws and local claims history.
Each service a physician bills has a set of relative value units (RVUs) assigned to these three categories. The geographic modifiers multiply against the corresponding RVUs before everything is added together. The formula looks like this: Work RVU × Work GPCI + Practice Expense RVU × PE GPCI + Malpractice RVU × Malpractice GPCI = Total RVU. That total is then multiplied by a national dollar conversion factor to produce the final payment amount.
How Payment Localities Are Defined
The country is divided into payment localities, and each locality gets its own set of three GPCI values. There are currently 112 total payment localities. Thirty-four of them cover an entire state as a single area, meaning every physician in that state receives the same geographic adjustment. The remaining localities are found in 16 states where costs vary enough within the state to justify finer distinctions.
California is the most granular example. Under a restructuring required by the Protecting Access to Medicare Act of 2014 and implemented in 2017, California went from 9 localities to 32 operational payment areas based on Metropolitan Statistical Area (MSA) boundaries defined by the Office of Management and Budget. This means a physician in San Francisco has a different GPCI than one in Fresno or Bakersfield, reflecting the significant cost-of-living gaps across the state.
How Much Payments Actually Vary
The differences are substantial enough to shift billions of dollars. A 2022 GAO analysis of 2018 payment data modeled what would happen under various hypothetical changes to geographic adjustments. If Congress removed the work GPCI floor (a policy that prevents certain areas from dropping below a baseline) along with a related one-quarter adjustment, localities below the national average would lose roughly $1.52 billion in annual payments, a 3.8% cut. Meanwhile, above-average localities would gain about $1.14 billion, a 4.3% increase.
Even smaller policy changes carry significant weight. Simply removing the work GPCI floor alone would reduce payments to below-average areas by $415.8 million annually. These numbers illustrate that geographic modifiers aren’t minor technical tweaks. They redistribute real money across the healthcare system.
The Work GPCI Floor
Congress has repeatedly intervened to set a floor of 1.0 on the physician work GPCI. Without this floor, areas where physician labor costs fall below the national average would receive less than the baseline payment for the work component. The floor essentially guarantees that no locality is penalized for having lower labor costs when it comes to the physician’s personal effort and skill.
This floor has never been made permanent. Instead, Congress extends it in short bursts. Most recently, Section 3206 of the American Relief Act, 2025, signed on December 21, 2024, extended the work GPCI floor through April 1, 2025. Each time the floor nears expiration, physicians in lower-cost areas face uncertainty about whether their payments will drop. The temporary nature of the floor has been a persistent source of frustration for rural and small-town practices that rely on it.
Impact on Rural and Underserved Areas
Geographic modifiers sit at the center of a longstanding tension in Medicare policy. They’re designed to reflect real cost differences, but critics argue they can also discourage physicians from practicing in areas that already struggle to attract providers. If a region has lower costs and therefore lower Medicare payments, the financial incentive to set up a practice there weakens further.
Research consistently shows that healthcare access declines as rurality increases. Metrics related to healthcare accessibility, including the density of surgical centers, hospitals with obstetric care, and mental health providers, are all inversely associated with how rural a county is. Nearly a quarter of rural counties in the United States show statistically significant declines in the density of hospitals providing obstetric care, with the strongest clustering in the rural Southeast. Dental, mental health, substance abuse, and surgical care all show significant access disparities among rural communities.
Geographic modifiers aren’t the sole cause of these gaps. Population density, workforce preferences, and infrastructure all play roles. But payment levels influence where physicians choose to practice, and the GPCI system means that the places with the fewest doctors often receive the lowest per-service payments. Programs like Federally Qualified Health Centers and Rural Health Clinics show more consistent penetration across rural areas, partly because they operate under different payment structures that don’t rely as heavily on GPCIs.
How the Indices Are Updated
CMS recalculates GPCIs periodically using data on local wages, office rents, and malpractice premiums. The practice expense GPCI draws on sources that track commercial rents and employee compensation in each locality. The malpractice GPCI uses actual premium data from insurers. When CMS standardizes Medicare payments to compare spending across regions, it specifically strips out the effects of geographic adjustments so that researchers can isolate actual differences in resource use from differences that simply reflect local cost structures.
The 2025 Medicare Physician Fee Schedule final rule confirmed that geographic adjusters continue to be applied to total RVUs to account for cost variation by area. Because the work GPCI floor was extended and the geographic adjustment factors remained unchanged from 2024, the standardization factors were set at 1.0000 to maintain budget neutrality.