Lydia Williams, PH.D.
NPI 1184721110 · Clinical Psychologist · Mount Vernon, IL
Enrolled with Medicare as Practitioner - Clinical Psychologist · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Lydia Williams, PH.D. is a Clinical Psychologist provider in Mount Vernon, IL (NPI 1184721110).
Provider details
- NPI number
- 1184721110
- Entity type
- Individual
- Primary specialty
- Clinical PsychologistBehavioral Health & Social Service Providers
- Credential
- PH.D.
- Sex
- Female
- Sole proprietor
- Yes
- License
- 071005322 (IL)
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
424 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 | 410 | $135 |
| Psychiatric Diagnostic Evaluation90791 | 14 | $166 |
Typical Medicare-allowed amounts for these services range $135–$166 (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
- 2006-09-20
- Last updated
- 2013-01-01
Frequently asked questions
- What is Lydia Williams's NPI number?
- Lydia Williams's National Provider Identifier (NPI) is 1184721110, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Lydia Williams's specialty?
- Lydia Williams is listed in the NPPES registry with a primary specialty of Clinical Psychologist (Behavioral Health & Social Service Providers).
- Where is Lydia Williams located?
- Lydia Williams's practice location on file with NPPES is 4230 Lincolnshire Dr, Mount Vernon, IL 62864-2189.
- What is Lydia Williams's phone number?
- The practice phone number listed in the NPPES registry for Lydia Williams is (618) 242-4205.
- Does Lydia Williams accept Medicare?
- Lydia Williams is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Lydia Williams's NPI active?
- Yes — Lydia Williams's NPI (1184721110) is active in the NPPES registry as of the last update on 2013-01-01.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.