Physician assistants (PAs) are legally required to have a relationship with a physician in every U.S. state, but “working under a doctor” looks very different depending on where and how a PA practices. In many settings, a PA sees patients, diagnoses conditions, and prescribes medications without a physician in the building or even in the same city. The formal requirement is a collaborative or supervisory agreement with a doctor, not necessarily moment-to-moment oversight.
What “Supervision” Actually Means
The word supervision is misleading because most people picture a doctor standing nearby, watching what the PA does. In practice, the requirement is usually a signed agreement between a PA and a physician that outlines what the PA can and cannot do. The physician doesn’t need to be present for every patient visit, and in many states, they don’t need to be in the same building at all.
Arkansas, for example, requires “continuous supervision” but defines it in a way that does not require the physician to be physically present when the PA treats patients. Hawaii uses similar language. In New Jersey, outpatient PAs only need their supervising physician to be reachable by phone or video. Inpatient settings in New Jersey are stricter, requiring the physician to be on-site at least intermittently.
So the legal reality is closer to “a doctor has agreed to be available and accountable” than “a doctor is watching over your shoulder.” Most PAs operate with significant day-to-day independence.
How Much Autonomy Varies by State
Each state sets its own rules for the PA-physician relationship, and there is wide variation. Some states use the word “supervision,” others use “collaboration,” and a few have moved toward giving PAs more independence by loosening older requirements. The specific terms of the agreement, including what procedures a PA can perform and what prescriptions they can write, are typically negotiated between the PA and the supervising physician within the boundaries state law allows.
California caps the ratio at four PAs per supervising physician for those providing direct patient care and prescribing medication. Other states set different limits or have no formal ratio cap at all. These ratios give a sense of how loosely the relationship can work: a single physician overseeing four PAs clearly cannot be present for all of their patient encounters.
Prescribing Rules Add Another Layer
PAs can prescribe medications in all 50 states, but controlled substances come with extra restrictions that tie back to the supervising physician. The strongest restrictions apply to Schedule II drugs, which include medications like oxycodone and amphetamine-based stimulants.
Georgia and Texas prohibit PAs from prescribing Schedule II medications entirely, though PAs in those states can prescribe less tightly controlled drugs (Schedules III through V). Arkansas and Missouri only allow PAs to prescribe hydrocodone combination products from the Schedule II category. In Arizona, Illinois, Montana, North Carolina, Pennsylvania, and South Dakota, PAs can prescribe Schedule II drugs but are limited to a 30-day supply. Some states also require the supervising physician to approve refills of Schedule II prescriptions.
For non-controlled medications like antibiotics, blood pressure drugs, and most everyday prescriptions, PAs generally have broad authority without needing a co-signature.
Rural PAs Often Practice With Far Less Oversight
The gap between legal requirements and daily reality is widest in rural areas, where physician shortages make close supervision impractical. A study of emergency department PAs found striking differences between rural and urban practice. Among rural PAs, 38% reported never having a physician present in the emergency department during their shifts, compared to 0% of urban PAs. Only 50% of rural PAs said a physician was always present, versus 98% in urban settings.
Rural PAs also handled a broader range of emergencies. They were more likely to manage cardiac arrest (67% vs. 44% of urban PAs), stroke (86% vs. 72%), multisystem trauma (83% vs. 70%), and critically ill children (82% vs. 65%). They performed advanced procedures like intubation and chest tube placement at significantly higher rates than their urban counterparts. Rural PAs were also less likely to have a physician evaluate their patients afterward, with 19% reporting that a physician never reviews all of their cases.
This isn’t a loophole. Rural health systems depend on PAs functioning with a high degree of autonomy because there simply aren’t enough physicians to staff every clinic and emergency room.
The Title Is Changing, but the Rules Aren’t
You may have noticed the profession shifting from “physician assistant” to “physician associate.” Oregon became the first state to officially adopt this change in June 2024 through legislation that replaced the old title throughout state law. The Oregon Medical Board clarified that the name change is purely cosmetic and does not affect any component of a PA’s practice or scope.
The name change reflects the profession’s view that “assistant” implies a level of dependence that doesn’t match how most PAs actually work. Other states are considering similar legislation, though each would need to pass its own law. If you see a provider identified as a “physician associate,” they have exactly the same training, licensing, and scope as someone called a “physician assistant.”
What This Means for Patients
If you’re seeing a PA for your care, a physician has formally agreed to collaborate with them, review certain aspects of their work, and be available for questions or complex cases. That physician may be in the same office, across town, or reachable by phone. The PA has completed a graduate-level medical education program and passed a national certification exam before being licensed by the state.
In practical terms, the PA treating you is making clinical decisions independently for the vast majority of visits. They consult the supervising physician when a case falls outside their expertise or their practice agreement, much the same way a physician would consult a specialist. The supervisory relationship exists as a safety net and legal framework, not as real-time direction of your care.