Variations in Physical Therapy Autonomy and Provider Density

In the United States, physical therapy is a cornerstone of modern healthcare, a service that roughly half of all people will rely on at some point in their lives. It is the most frequently used specialized medical service, surpassing even chiropractic care and substance use treatment combined. Yet, while the medical community knows how vital these therapists are for helping people recover from injuries, manage chronic pain, and regain strength after surgery, the rules that govern their work remain a mystery to most. In the world of healthcare policy, these rules are known as the "scope of practice." This term simply describes the specific tasks a licensed professional is legally allowed to perform. Just as a driver's license dictates where and how a person can drive, a physical therapist's license determines what treatments they can offer, whether they can diagnose a condition without a doctor's referral, and what equipment they can order. These rules are not uniform; they are written by the legislatures of each individual state, creating a patchwork of regulations where a therapist in one state might have broad freedom, while a colleague just across the border faces strict limitations.

For decades, researchers have studied how these rules affect doctors, nurses, and physician assistants, finding that giving them more freedom often improves access to care without harming patients. However, physical therapists have been largely left out of this conversation. Until now, there has been no comprehensive map of the laws that dictate what physical therapists can and cannot do across the country. A team of researchers from West Virginia University has set out to fill this gap. They spent years building the first-ever database that tracks the specific legal permissions for physical therapists in every state and the District of Columbia. Their goal was to see if these varying laws actually change the number of clinics and therapists available to the public. By turning complex legal codes into a clear, comparable score, they discovered a quiet but significant pattern: the stricter the rules, the fewer the clinics.

The researchers began by gathering the actual laws and regulations from all fifty states and the District of Columbia. They did not rely on summaries or opinions; they read the legal texts themselves to see exactly what was written. A team of undergraduate students, law students, and legislative analysts worked together to verify the details, ensuring that the data reflected the law as it was written, not how it might be interpreted by local boards. They focused on eight specific areas where physical therapists often need permission to work. These included the ability to treat patients through telehealth, perform a technique called dry needling where thin needles are inserted into tight muscles, conduct initial evaluations of a patient's needs, order X-rays or other imaging like MRIs, provide wound care for open sores, and perform specialized diagnostic tests. For each of these areas, they noted whether a therapist could do the task freely, if they needed extra training or supervision, if they could only order the test but not do it themselves, or if they were completely banned from the activity.

To make sense of this vast amount of information, the team created a single score for each state, ranging from zero to ten. A score of zero meant the state had the fewest restrictions, allowing therapists to perform the widest range of tasks with the least amount of red tape. A score of ten represented the most restrictive environment, where therapists faced many bans or heavy requirements. For example, in West Virginia, therapists can treat patients via telehealth and perform dry needling without any extra hurdles, earning them a low score for those categories. However, they cannot order X-rays, which adds to their overall restrictiveness score. When the team added up the scores for all eight areas and adjusted them to fit the zero-to-ten scale, they found that the landscape varied wildly. Some states were very open, while others kept tight control over what therapists could do.

With this new map of regulations in hand, the researchers turned to the question of supply. They wanted to know if these legal barriers actually kept physical therapy clinics from opening. They looked at business data from 2024, counting the number of physical therapy establishments and the number of people working in them across nearly three thousand counties. When they compared the restrictiveness scores to the number of clinics, a clear relationship emerged. The data showed that for every single point a state's restrictiveness score increased, there were fewer physical therapy businesses per ten thousand residents. This was not a minor fluctuation; the association was strong and statistically significant. In simpler terms, states with more freedom for their therapists tended to have more clinics, while states with tighter rules had fewer.

The researchers were careful to note that this finding shows a connection, not necessarily a cause-and-effect chain that is fully proven. It is possible that states with a large, influential group of physical therapists are the ones who successfully lobby for fewer restrictions, rather than the laws themselves creating the clinics. There could also be other hidden factors, such as local demand for care or insurance payment rules, that influence both the laws and the number of businesses. However, the pattern was consistent even when the researchers accounted for other variables like population density, median income, and the percentage of people living in rural areas. The study suggests that the legal environment plays a real role in shaping the healthcare landscape.

This work is particularly timely as the population ages and the need for physical therapy grows. The study highlights that the rules written in state legislatures are not just bureaucratic details; they have a tangible impact on the availability of care. By providing the first detailed dataset on this topic, the researchers have given policymakers and economists a tool to understand how changing the law might change the number of providers available to patients. While the study is limited to a single point in time and relies on written laws rather than how they are enforced in practice, it opens the door for future research. It suggests that if states wish to increase access to physical therapy, especially in areas where providers are scarce, examining and potentially loosening these regulatory restrictions could be a practical step forward. The map is now drawn, and the next step is to see how the terrain changes as the laws evolve.