John Williamson, PHD
NPI 1215224977 · Clinical Neuropsychologist · Gainesville, FL
Enrolled with Medicare as Practitioner - Clinical Psychologist · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Provider details
- NPI number
- 1215224977
- Entity type
- Individual
- Primary specialty
- Clinical NeuropsychologistBehavioral Health & Social Service Providers
- Credential
- PHD
- Sex
- Male
- Sole proprietor
- No
- License
- PY8262 (FL)
Specialties & taxonomies
Behavioral Health & Social Service Providers
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure28% of score
14 yrs in NPPES registry
- Profile completeness28% of score
100% of core fields populated
- Practice footprint17% of score
1 documented practice location
- Medicare service volume (vs. specialty peers)28% of score
235 Medicare services, 2024 (ranked within specialty)
Medicare volume is ranked against active providers in the same specialty. Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our methodology.
What this provider does (Medicare)
Based on Medicare fee-for-service claims, 2024; not all care is captured.
| Service (HCPCS) | Medicare services | Typical Medicare-allowed (2024) |
|---|---|---|
| Administration of Psychological Or Neuropsychological Test By Technician, Each Additional 30 Minutes96139 | 137 | $34 |
| Evaluation of Neuropsychological Test, Each Additional Hour96133 | 27 | $97 |
| Evaluation of Neuropsychological Test, First Hour96132 | 25 | $128 |
| Administration of Psychological Or Neuropsychological Test By Technician, First 30 Minutes96138 | 25 | $33 |
| Psychiatric Diagnostic Evaluation90791 | 21 | $173 |
Typical Medicare-allowed amounts for these services range $33–$173 (2024). The Medicare-allowed amount is what Medicare recognizes for a service under fee-for-service — a reference figure for 2024, not a price quote and not what you would be billed. Medicare Part B covers roughly an eighth of all NPIs (65+ skew); services with fewer than 11 beneficiaries are suppressed by CMS. Source: CMS Medicare Physician & Other Practitioners, by Provider & Service.
Practice location
Mailing address
Registry dates
- Enumerated
- 2011-07-01
- Last updated
- 2012-01-18
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.