Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum Sole proprietor

Dr. Douglas Lon William, PH.D.

Clinical Child & Adolescent Psychologist in Jericho, NY · enumerated 2007.

Data current as of Jul 13, 2026 · sourced from CMS NPPES

National Provider Identifier

1871632489

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Registry record

Entity type Individual (Type 1)

Name Dr. Douglas Lon William

Credential PH.D.

Sex Male

Practice address Jericho, NY, 11753

Phone (516) 931-0752

Enumeration date Feb 6, 2007

Last updated in NPPES Jul 8, 2007

Street address withheld: NPPES sole-proprietor addresses can be home addresses. See our data policy.

Taxonomy & licenses

103TC2200X Clinical Child & Adolescent Psychologist Behavioral Health & Social Service Providers · License 6159 (NY) Primary

PHD · Doctor of Philosophy: A doctoral degree; in healthcare often held by clinical psychologists and researchers. About the PHD credential

What is an NPI number?

A National Provider Identifier (NPI) is a unique 10-digit number that CMS assigns to every U.S. healthcare provider and organization under HIPAA. Type 1 NPIs identify individual providers; Type 2 NPIs identify organizations. The NPI appears on insurance claims, prescriptions, and credentialing paperwork, and never changes, even if the provider moves or changes specialty.

Read the full guide → Validate an NPI →

Frequently asked questions

Where does Douglas William practice?

The practice location on file with NPPES is in Jericho, NY. Providers can have multiple locations; NPPES lists the primary practice address.

What is the NPI number for Douglas William?

The National Provider Identifier (NPI) for Douglas William is 1871632489, a Type 1 (individual) record in the CMS NPPES registry.

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2007-07-08.