Healthcare Insights
Taxonomy versus claims-based specialties
When healthcare providers register for a National Provider Identifier (NPI) number, they select a taxonomy that reflects their specialization and education. This data point, however, may become outdated as a provider finishes training or branches into a sub-specialty focus.
To more accurately reflect a provider’s practice patterns, we assign them a claims-based specialty in our PhysicianView product.
In the list below, we spotlight differences in taxonomy-based specialties and claims-based specialties to see areas where our data better classifies the providers in our PhysicianView product.
| Taxonomy code | NPI taxonomy description | Claims-based specialty | Number of providers | Explore dataset |
|---|---|---|---|---|
| 225X00000X | Therapy - Occupational Therapist | Pediatric Physical Therapy | 3141 | Explore |
| 207Q00000X | Family Practice | Physical Therapy | 2724 | Explore |
| 207Q00000X | Family Practice | Emergency Medicine | 2510 | Explore |
| 207R00000X | Internal Medicine | Physical Therapy | 2331 | Explore |
| 225XP0200X | Pediatric Medicine | Occupational Therapy | 2263 | Explore |
| 207X00000X | Surgery - Orthopedic Surgery | Physical Therapy | 1669 | Explore |
| 363LP0200X | Nurse - Nurse Practitioner | Pediatric Medicine | 1606 | Explore |
| 2251P0200X | Pediatric Medicine | Physical Therapy | 1516 | Explore |
| 208000000X | Pediatric Medicine | Speech Language Pathology | 1387 | Explore |
| 363LP0808X | Nurse - Nurse Practitioner | Psychiatry | 1383 | Explore |
| 207R00000X | Internal Medicine | Pediatric Medicine | 1117 | Explore |
| 207R00000X | Internal Medicine | Emergency Medicine | 935 | Explore |
| 207RC0000X | Internal Medicine | Cardiology | 933 | Explore |
| 207RN0300X | Internal Medicine | Nephrology | 916 | Explore |
| 207RG0100X | Internal Medicine | Gastroenterology | 898 | Explore |
Fig 1. Data from the Definitive Healthcare PhysicianView product. Data examines where the taxonomy-based primary specialty is different from the claims-based specialty. Claims-based specialty is a proprietary designation from Definitive Healthcare. Data is sourced from proprietary research, the NPI registry, and Physician Compare. Data accessed April 2025.
Claims-based specialty better categorizes more than 12,000 internal medicine doctors
Eight of the 15 pairs of NPI-based and claims-based specialties provide more granular therapy area information for 12,364 providers identified with an internal medicine or family medicine taxonomy code. These physicians are more accurately described as cardiology, emergency medicine, gastroenterology, physical therapy, pediatric medicine, and nephrology specialists when their diagnosis and procedure activity are taken into account.
Why are claims-based medical specialties important?
Compared to self-reported taxonomies, claims-based specialties in PhysicianView use healthcare data and analytics to better represent the type of clinical activity a provider performs. It allows for categorization of physicians based on their expertise and provides an up-to-date view of the procedures they’re performing.
For example, if a rehabilitative medicine professional association wants to target all physical therapy providers, they would miss more than 5,000 potential contacts that have an internal medicine or family medicine taxonomy but bill predominantly for physical therapy codes.
Or, if a biopharma company wants to know more about doctors who treat kidney disease patients, they could miss the 900-plus providers with a nephrology claims-based specialty who have a different taxonomy-based specialty.
Is a taxonomy code the same as a specialty?
A medical specialty is the particular field of medicine that a doctor chooses to study and practice within. Definitive Healthcare tracks 46 distinct specialty categories and 128 subspecialty categories within our platform.
A taxonomy code is a unique 10-character code that identifies a provider’s classification and specialty as established by the National Uniform Claim Committee.
What is the difference between taxonomy and NPI?
An NPI is the unique identification number assigned to providers who participate in Medicare. The NPI was standardized through the Health Insurance Portability and Accountability Act.
Providers self-report taxonomy codes when applying for an NPI, which can result in mismatches between their specialties and actual scopes of practice as they progress throughout their careers.
Learn more
Healthcare Insights are developed with healthcare commercial intelligence from the Definitive Healthcare platform. Want even more insights? Learn how to leverage NPI target lists for strategic advertisement placements. Or start a free trial now and get access to the latest data, analytics, and insights on hospitals, physicians, and other healthcare providers.
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