Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

William Stephen Slavin, LLP LMSW

Psychologist in Traverse City, MI · enumerated 2006.

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

National Provider Identifier

1154409373

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Registry record

Entity type Individual (Type 1)

Name William Stephen Slavin

Credential LLP LMSW

Sex Male

Practice address 105 Hall St, Suite A, Traverse City, MI, 49684

Phone (231) 922-4850

Fax (231) 935-3856

Enumeration date Nov 2, 2006

Last updated in NPPES Sep 11, 2025

Taxonomy & licenses

103T00000X Psychologist Behavioral Health & Social Service Providers · License 6301003757 (MI) Primary

104100000X Social Worker Behavioral Health & Social Service Providers · License 6801014929 (MI) Secondary

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

Is NPI 1154409373 active?

Yes, as of the latest NPPES snapshot, NPI 1154409373 is active (record last updated 2025-09-11).

How do I verify William Slavin's NPI record?

Cross-check NPI 1154409373 against the official CMS registry at npiregistry.cms.hhs.gov. This page mirrors the same public NPPES data with a monthly snapshot.

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2025-09-11.