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

Published:November 01, 2022DOI:



      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.


      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'


      Subscribe to Journal of Surgical Research
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect


        • NPI
        What You Need to Know.
        Medicare Learning Network, 2021 (MLN909434)
        • Find Your Taxonomy Code
        • Lynch G.
        • Nieto K.
        • Puthenveettil S.
        • et al.
        Attrition rates in neurosurgery residency: analysis of 1361 consecutive residents matched from 1990 to 1999.
        J Neurosurg. 2015; 122: 240-249
        • Coombs L.A.
        • Max W.
        • Kolevska T.
        • Tonner C.
        • Stephens C.
        Nurse practitioners and physician assistants: an underestimated workforce for older adults with cancer.
        J Am Geriatr Soc. 2019; 67: 1489-1494
        • Martin A.
        • Chen M.L.
        • Chatterjee A.
        • et al.
        Specialty classifications of physicians who provide neurocritical care in the United States.
        Neurocrit Care. 2019; 30: 177-184
        • Shih Y.-C.T.
        • Kim B.
        • Halpern M.T.
        State of physician and pharmacist oncology workforce in the United States in 2019.
        Jco Oncol Pract. 2021; 17: e1-e10
        • Acuña A.J.
        • Sato E.H.
        • Jella T.K.
        • et al.
        How long will it take to reach gender parity in orthopaedic surgery in the United States? An analysis of the national provider identifier registry.
        Clin Orthop Relat Res. 2021; 479: 1179-1189
        • Schwaitzberg S.D.
        • Scott D.J.
        • Jones D.B.
        • et al.
        Threefold increased bile duct injury rate is associated with less surgeon experience in an insurance claims database.
        Surg Endosc. 2014; 28: 3068-3073
        • Carrubba A.R.
        • Osagiede O.
        • Spaulding A.C.
        • et al.
        Variability between individual surgeons in route of hysterectomy for patients with endometrial cancer in Florida.
        Surg Oncol. 2019; 31: 55-60
        • Dubuque E.M.
        • Yingling M.E.
        • Allday R.A.
        The misclassification of behavior analysts: how national provider identifiers (NPIs) fail to adequately capture the scope of the field.
        Behav Anal Pract. 2021; 14: 214-229
        • Newgard C.
        • Malveau S.
        • Staudenmayer K.
        • et al.
        Evaluating the use of existing data sources, probabilistic linkage, and multiple imputation to build population-based injury databases across phases of trauma care.
        Acad Emerg Med. 2012; 19: 469-480
        • Rhee D.
        • Papandria D.
        • Yang J.
        • et al.
        Comparison of pediatric surgical outcomes by the surgeon’s degree of specialization in children.
        J Pediatr Surg. 2013; 48: 1657-1663
        • Mabry S.E.
        • Cichos K.H.
        • McMurtrie J.T.
        • Pearson J.M.
        • McGwin G.
        • Ghanem E.S.
        Does surgeon fellowship training influence outcomes in hemiarthroplasty for femoral neck fracture?.
        J Arthroplast. 2019; 34: 1980-1986
        • Kulaylat A.S.
        • Pappou E.
        • Philp M.M.
        • et al.
        Emergent colon resections.
        Dis Colon Rectum. 2019; 62: 79-87
        • Clark N.V.
        • Gujral H.S.
        • Wright K.N.
        Impact of a fellowship-trained minimally invasive gynecologic surgeon on patient outcomes.
        Jsls J Soc Laparoendosc Surg. 2017; 21 (e2017.00037): 1-6
        • Cataneo J.L.
        • Veilleux E.
        • Lutfi R.
        Impact of fellowship training on surgical outcomes after appendectomies: a retrospective cohort study.
        Surg Endosc. 2021; 35: 4581-4584
        • McCutcheon B.A.
        • Hirshman B.R.
        • Gabel B.C.
        • et al.
        Impact of neurosurgeon specialization on patient outcomes for intracranial and spinal surgery: a retrospective analysis of the Nationwide Inpatient Sample 1998–2009.
        J Neurosurg. 2018; 128: 1578-1588
        • Johnston M.J.
        • Singh P.
        • Pucher P.H.
        • et al.
        Systematic review with meta-analysis of the impact of surgical fellowship training on patient outcomes.
        Br J Surg. 2015; 102: 1156-1166
        • Nayak J.G.
        • Drachenberg D.E.
        • Mau E.
        • et al.
        The impact of fellowship training on pathological outcomes following radical prostatectomy: a population based analysis.
        Bmc Urol. 2014; 14: 1-6
        • Lim S.L.
        • Puechl A.M.
        • Broadwater G.
        • et al.
        Gender variation in Medicare utilization and payments in gynecologic oncology.
        Gynecol Oncol. 2019; 154: 602-607