2026 NPPES data Clinical Child & Adolescent Psychologist NPI 1588623938 PHD
Verify on CMS →

WALTER GILLIAM, PHD

Clinical Child & Adolescent Psychologist in NEW HAVEN, Connecticut. CMS National Plan and Provider Enumeration System profile including specialty classification, practice address, and Medicare prescribing data when reported.

Federal data — no proprietary rating. PlainDoctor publishes the actual CMS NPPES and Medicare records — NPI registration, specialty, practice location, and prescribing data — without a composite score or editorial opinion on top. Every field traces to a federal source.
What the federal data reveals: WALTER GILLIAM, PHD is a Clinical Child & Adolescent Psychologist ([object Object]) practicing in NEW HAVEN, Connecticut .

What stands out: WALTER GILLIAM, PHD specializes in Clinical Child & Adolescent Psychologist and practices in NEW HAVEN, Connecticut, listed in the federal CMS National Provider Identifier registry. Every detail on this page comes straight from federal CMS records, with no proprietary rating applied.

WALTER GILLIAM, PHD at a glance

Quality data not reported

NPI registry status

Active

Issued 03/22/2006

NPI 1588623938

Primary specialty

Clinical Child & Adolescent Psychologist

Niche

4,617 US NPIs in this specialty

Specialty distribution in Connecticut

How Clinical Child & Adolescent Psychologist compares to other specialties among Connecticut providers

Connecticut providers

Clinical Child & Adolescent Psychologist share within Connecticut

1. Clinical Child & Adolescent Psychologist42%2. Internal medicine21%3. Family medicine17%4. Surgical12%5. Pediatric8%
Clinical Child & Adolescent Psychologist share within Connecticut

Specialty board-certification context

Estimated specialty board-certified rate — Clinical Child & Adolescent Psychologist (ABMS / AOA reference)

Quality data not reported
Est. board-certified rate
78%
Clinical Child & Adolescent Psychologist ABMS/AOA estimate

Est. board-certified rate (Clinical Child & Adolescent Psychologist) — ABMS / AOA estimate

0%100%78%
Est. board-certified rate (Clinical Child & Adolescent Psychologist) — ABMS / AOA estimate

The Merit-based Incentive Payment System (MIPS) scores providers 0–100 across four performance categories: Quality, Cost, Promoting Interoperability, and Improvement Activities, weighted under 42 CFR §414.1380. Reporting is voluntary for many small practices, so absence of a MIPS score is not a quality signal.

Board certification through an ABMS or AOA member board signals voluntary post-licensure examination plus continuous Maintenance of Certification cycles. Verify any individual provider's status through certificationmatters.org (ABMS) or osteopathic.org (AOA).

WALTER GILLIAM, PHD is a Clinical Child & Adolescent Psychologist provider practicing in NEW HAVEN, Connecticut, according to the CMS National Plan and Provider Enumeration System (NPPES). Credentials: PHD. NPI: 1588623938. This profile includes practice location, specialty classification, and organizational affiliations from the CMS provider registry. Provider information is self-reported to CMS and updated monthly.

WALTER GILLIAM, PHD appears in the CMS NPPES registry as a Clinical Child & Adolescent Psychologist provider holding PHD credentials at 800 HOWARD AVENUE, NEW HAVEN, CT, 06519, with a listed phone of (203) 785-2140. NPI 1588623938 was issued on 03/22/2006. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what GILLIAM most recently submitted to CMS rather than a vetted directory listing, which is why patients should always confirm the practice is still at this location before scheduling.

Medicare Part D prescribing data is not currently published for this NPI, which typically means the provider either wrote fewer than 11 Part D claims in the most recent reporting year, does not participate in Medicare, or practices in a specialty that rarely prescribes outpatient drugs. Absence of prescribing data is not a quality signal — many Clinical Child & Adolescent Psychologist providers operate outside Part D entirely.

Clinical Child & Adolescent Psychologist is a narrow specialty nationwide, with 4,617 enrolled providers across 53 states and an average of 364 Part D claims per prescriber, so the context for interpreting these metrics differs meaningfully from a primary-care baseline. Important: PlainDoctor is a directory of publicly available government data, not medical advice, a malpractice database, or a quality rating. Inclusion here does not imply a recommendation, and absence of complaints or sanctions on this page does not mean none exist — always verify credentials through the NPPES NPI Registry, your state medical board, and the ABMS or AOA before making healthcare decisions.

Practice Address

800 HOWARD AVENUE
NEW HAVEN, CT 06519

Provider Details

NPI 1588623938
Specialty Clinical Child & Adolescent Psychologist
Credentials PHD
Gender Male
NPI Issued 03/22/2006

Clinical Child & Adolescent Psychologist Overview

How WALTER GILLIAM, PHD fits within the Clinical Child & Adolescent Psychologist landscape nationally.

4,617
Clinical Child & Adolescent Psychologist Providers in US
53
States with Clinical Child & Adolescent Psychologist
364
Avg Claims per Provider

Nearby Clinical Child & Adolescent Psychologist Providers in Connecticut

Other clinicians with the same primary specialty enrolled in Connecticut, drawn from the same CMS NPPES roster as GILLIAM.

Compare Clinical Child & Adolescent Psychologist nationally: see state-by-state distribution →

Frequently Asked Questions

What is WALTER GILLIAM, PHD's specialty?
WALTER GILLIAM, PHD specializes in Clinical Child & Adolescent Psychologist and practices in NEW HAVEN, Connecticut. Credentials: PHD.
Where is WALTER GILLIAM, PHD located?
WALTER GILLIAM, PHD is located at 800 HOWARD AVENUE, NEW HAVEN, CT, 06519. Phone: (203) 785-2140.
What is WALTER GILLIAM, PHD's NPI number?
WALTER GILLIAM, PHD's National Provider Identifier (NPI) is 1588623938, issued on 03/22/2006.
How many Clinical Child & Adolescent Psychologist providers are there in the US?
There are 4,617 Clinical Child & Adolescent Psychologist providers across 53 states in the US. The average Clinical Child & Adolescent Psychologist provider writes 364 Medicare Part D claims per year.
Does WALTER GILLIAM, PHD accept Medicare?
WALTER GILLIAM, PHD appears in CMS Medicare data. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify WALTER GILLIAM, PHD's credentials?
WALTER GILLIAM, PHD's NPI is 1588623938 with credentials PHD. You can verify this through the NPPES NPI Registry, check state medical board records, and confirm board certification through the ABMS or AOA.

Data Sources

Provider Directory
CMS National Plan and Provider Enumeration System (NPPES), download.cms.gov/nppes, updated monthly. Contains NPI, specialty, credentials, and practice location.
Specialty Classification
NUCC Health Care Provider Taxonomy (nucc.org), the industry standard for classifying provider specialties in Medicare and Medicaid billing.
Limitations
Provider data is self-reported to CMS. Prescribing data reflects Medicare Part D only and does not include commercial insurance, Medicaid, or cash prescriptions. Claims below 11 beneficiaries are suppressed by CMS for privacy.

See our complete data methodology for details on how we collect and process government data.

Data as of April 2026 (NPPES) / 2023 (Medicare Part D). Source: Centers for Medicare & Medicaid Services (CMS).

Disclaimer: Data from CMS NPPES and Medicare Part D. PlainDoctor does not rate or rank providers. Provider information is self-reported and may not be current. Always verify information directly with the provider. About · Methodology