The National Provider Identifier Taxonomy: Does it Align With a Surgeon's Actual Clinical Practice?

The taxonomy code(s) associated with each National Provider Identifier (NPI) entry should characterize the provider's role (e.g., physician) and any specialization (e.g., orthopedic surgery). While the intent of the taxonomy system was to monitor medical appropriateness and the expertise of care provided, this system is now being used by researchers to identify providers and their practices. It is unknown how accurate the taxonomy codes are in describing a provider's true specialization.

Department websites of orthopedic surgery and general surgery from three large academic institutions were queried for practicing surgeons. The surgeon's specialty and subspeciality information listed was compared to the provider's taxonomy code(s) listed on the National Plan and Provider Enumeration System (NPPES). The match rate between these data sources was evaluated based on the specialty, subspecialty, and institution.

There were 295 surgeons (205 general surgery and 90 orthopedic surgery) and 24 relevant taxonomies (8 orthopedic and 16 general or plastic) for analysis. Of these, 294 surgeons (99%) selected their general specialty taxonomy correctly, while only 189 (64%) correctly chose an appropriate subspecialty. General surgeons correctly chose a subspecialty more often than orthopedic surgeons (70 versus 51%, P = 0.002). The institution did not affect either match rate, however there were some differences noted in subspecialty match rates inside individual departments.

In these institutions, the NPI taxonomy is not accurate for describing a surgeon's subspecialty or actual practice. Caution should be taken when utilizing this variable to describe a surgeon's subspecialization as our findings might apply in other groups.