William Sieber, PH.D.
NPI 1851413165 · Clinical Psychologist · San Diego, CA
Enrolled with Medicare as Practitioner - Clinical Psychologist · source: CMS PECOS Public Provider Enrollment (2026.04.01)
William Sieber, PH.D. is a Clinical Psychologist provider in San Diego, CA (NPI 1851413165).
Provider details
- NPI number
- 1851413165
- Entity type
- Individual
- Primary specialty
- Clinical PsychologistBehavioral Health & Social Service Providers
- Credential
- PH.D.
- Sex
- Male
- Sole proprietor
- No
- License
- 19435 (CA)
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
19 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
129 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) |
|---|---|---|
| Psychotherapy, 1 Hour90837 | 118 | $158 |
| Psychiatric Diagnostic Evaluation90791 | 11 | $179 |
Typical Medicare-allowed amounts for these services range $158–$179 (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
- 2007-04-06
- Last updated
- 2019-02-05
Frequently asked questions
- What is William Sieber's NPI number?
- William Sieber's National Provider Identifier (NPI) is 1851413165, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is William Sieber's specialty?
- William Sieber is listed in the NPPES registry with a primary specialty of Clinical Psychologist (Behavioral Health & Social Service Providers).
- Where is William Sieber located?
- William Sieber's practice location on file with NPPES is 200 W Arbor Dr, San Diego, CA 92103-9000.
- What is William Sieber's phone number?
- The practice phone number listed in the NPPES registry for William Sieber is (800) 926-8273.
- Does William Sieber accept Medicare?
- William Sieber is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is William Sieber's NPI active?
- Yes — William Sieber's NPI (1851413165) is active in the NPPES registry as of the last update on 2019-02-05.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.