2026 NPPES data Physician Assistant NPI 1902360605
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WILLIAM SLAGER

Physician Assistant in KENTWOOD, Michigan. 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.
Prescribing volume
2K
Medicare Part D claims · 236 beneficiaries · Physician Assistant avg: 790
Generic prescribing
79%
generic claims · 21% brand-name · higher generic rates reduce patient out-of-pocket costs
Industry payments
$45.77
1 payments · CMS Open Payments (Sunshine Act)

What the federal data shows

WILLIAM SLAGER filed 1,568 Medicare Part D claims in 2023 as a Physician Assistant in KENTWOOD, Michigan, prescribing 79% generic.

2K
Part D claims, 2023
79%
generic prescribing
$45.77
industry payments (Sunshine Act)

Every figure on this page comes straight from federal CMS records (NPPES, Medicare Part D, MIPS, Open Payments) — no proprietary rating or editorial opinion is applied.

WILLIAM SLAGER's Medicare Part D volume vs every U.S. prescriber

Total Medicare Part D claims, 2023 — across all CMS prescribers nationally

1,568 Top 19% higher than 81% of 1,370,886 prescribers

0–200: 670,926 prescribers (49%). Below this entry. 200–400: 182,923 prescribers (13%). Below this entry. 400–600: 90,619 prescribers (7%). Below this entry. 600–800: 56,224 prescribers (4%). Below this entry. 800–1,000: 40,919 prescribers (3%). Below this entry. 1,000–1,200: 31,827 prescribers (2%). Below this entry. 1,200–1,400: 26,224 prescribers (2%). Below this entry. 1,400–1,600: 21,710 prescribers (2%). This entry sits in this band. 1,600–1,800: 19,072 prescribers (1%). Above this entry. 1,800–2,000: 16,451 prescribers (1%). Above this entry. 2,000–2,200: 213,991 prescribers (16%). Above this entry. This provider 0 2K+ every Part D prescriber (claims/yr), bucketed by value

Each bar is a band; taller bars hold more prescribers. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.

Source CMS Medicare Part D Prescriber Public Use File · 2023

What does the federal data show about WILLIAM SLAGER?

Quality data not reported

NPI registry status

Active

Issued 01/27/2019

NPI 1902360605

Primary specialty

Physician Assistant

High-volume

149,975 US NPIs in this specialty

Medicare Part D claims

1,568 98% vs specialty avg

2023 prescription claims

Specialty avg: 790

Specialty distribution in Michigan

How Physician Assistant compares to other specialties among Michigan providers

Michigan providers

Physician Assistant share within Michigan

1. Physician Assistant42%2. Internal medicine21%3. Family medicine17%4. Surgical12%5. Pediatric8%
Physician Assistant share within Michigan

Specialty board-certification context

Estimated specialty board-certified rate — Physician Assistant (ABMS / AOA reference)

Quality data not reported
Est. board-certified rate
78%
Physician Assistant ABMS/AOA estimate

Est. board-certified rate (Physician Assistant) — ABMS / AOA estimate

0%100%78%
Est. board-certified rate (Physician Assistant) — 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).

WILLIAM SLAGER appears in the CMS NPPES registry as a Physician Assistant provider at 1900 44TH ST SE, KENTWOOD, MI, 49508, with a listed phone of (616) 685-1808. NPI 1902360605 was issued on 01/27/2019. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what SLAGER 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 records for calendar year 2023 show 1,568 prescription claims written by this provider, covering 236 Medicare beneficiaries and totaling roughly $890K in drug spend, split 21% brand-name and 79% generic by claim count. These figures capture only Medicare Part D — commercial insurance, Medicaid, and cash-pay prescriptions are not included, and any drug-beneficiary cell under 11 is suppressed by CMS for patient privacy.

Physician Assistant is a high-volume specialty nationwide, with 149,975 enrolled providers across 56 states and an average of 790 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

1900 44TH ST SE
KENTWOOD, MI 49508

Provider Details

NPI 1902360605
Specialty Physician Assistant
Gender Male
NPI Issued 01/27/2019

Hospital and facility affiliations

Facilities where WILLIAM SLAGER bills Medicare from. Star ratings (1-5) are CMS Hospital Compare's "Hospital overall rating" — a composite of mortality, readmission, patient experience, safety, timely care, and efficient use of medical imaging measures. Source: CMS Care Compare.

ADVANTAGE HEALTH/SAINT MARY'S MEDICAL GROUP
CALEDONIA, MI

Affiliations sourced from CMS Doctors and Clinicians National Downloadable File; hospital ratings from CMS Hospital General Information dataset (cross-referenced by facility name + state).

Industry payments received (2024) — CMS Open Payments transparency data

The federal Physician Payments Sunshine Act (part of the Affordable Care Act) requires drug and medical-device manufacturers + group purchasing organizations to publicly report payments and other transfers of value to physicians and teaching hospitals. The data below covers 2024 for WILLIAM SLAGER. Source: openpaymentsdata.cms.gov.

Total received

$46

Largest payer

Lundbeck LLC

Most common payment type

Food and Beverage

Industry payments are not necessarily indicators of bias — they include research funding, consulting fees for evidence-based work, royalties for inventions, food at conferences, and similar items. The disclosure exists for transparency. Read our methodology for how we interpret this data.

License & disciplinary context — Michigan MI-BOM 2023 annual report

Aggregate state board data only — NOT a determination of any individual provider's status. The figures below describe statewide disciplinary activity across all ~41K Michigan medical licensees in 2023 — they are NOT specific to WILLIAM SLAGER. To verify WILLIAM SLAGER's current license status, search the MI-BOM public license lookup directly, or check the Federation of State Medical Boards (FSMB) verification service.

123
Total board actions, Michigan 2023
Across 120 cases
3.00
Actions per 1,000 licensees
Michigan statewide rate
probation
Most common action type
44 cases

MI-BOM publishes annual disciplinary statistics as part of public-record reporting under each state's Administrative Procedure Act. See the full breakdown by action type and year on the Michigan disciplinary trends page. Cross-checked against FSMB U.S. Medical Regulatory Trends.

Brand vs generic prescribing mix · Typical

WILLIAM SLAGER — brand share 21.0%
Specialty average (est.)

21% brand-name claims vs 79% generic, on 1,568 2023 Medicare Part D claims.

The federal Medicare Part D Generic Dispensing Rate national benchmark sits near 90% generic / 10% brand for primary-care prescribers, per CMS Office of the Actuary 2024 estimates. Higher brand share is common in specialty prescribing where generic equivalents are not available.

Medicare Part D Prescribing Data

CMS Medicare Part D prescriber-level data for calendar year 2023.

1,568
Total Claims
$890K
Total Drug Cost
236
Medicare Beneficiaries

Prescribing Breakdown

30-Day Fills
2,249
Total Day Supply
64,089
Brand vs Generic
21% brand / 79% generic
Brand Drug Cost
$660K
Generic Drug Cost
$225K

Patient Demographics

Average Patient Age
58.7 years
Avg HCC Risk Score
1.30
Gender Split
61% female / 39% male
Age Distribution
<65: 138, 65-74: 70, 75-84: N/A, 85+: N/A

Top Prescribed Drugs (Medicare Part D)

Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.

What WILLIAM SLAGER prescribes most

Top Medicare Part D drugs by claim count, 2023

claims
Source CMS Medicare Part D Prescriber Public Use File As of 2023
Drug Claims
Lamotrigine
147
Levetiracetam
76
Aimovig Autoinjector
Erenumab-Aooe
72
Gabapentin
70
Dalfampridine Er
Dalfampridine
60
Divalproex Sodium Er
Divalproex Sodium
59
Lacosamide
59
Tizanidine Hcl
57
Zonisamide
53
Clobazam
48

* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.

Physician Assistant Overview

How WILLIAM SLAGER fits within the Physician Assistant landscape nationally.

149,975
Physician Assistant Providers in US
56
States with Physician Assistant
790
Avg Claims per Provider

WILLIAM SLAGER's 1,568 claims are above the specialty average of 790.

Nearby Physician Assistant Providers in Michigan

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

Compare Physician Assistant nationally: see state-by-state distribution →

Frequently Asked Questions

What is WILLIAM SLAGER's specialty?
WILLIAM SLAGER specializes in Physician Assistant and practices in KENTWOOD, Michigan.
How much does WILLIAM SLAGER prescribe under Medicare Part D?
In 2023, WILLIAM SLAGER wrote 1,568 Medicare Part D claims totaling $890K in drug costs for 236 beneficiaries.
Where is WILLIAM SLAGER located?
WILLIAM SLAGER is located at 1900 44TH ST SE, KENTWOOD, MI, 49508. Phone: (616) 685-1808.
What is WILLIAM SLAGER's NPI number?
WILLIAM SLAGER's National Provider Identifier (NPI) is 1902360605, issued on 01/27/2019.
Does WILLIAM SLAGER prescribe more brand-name or generic drugs?
WILLIAM SLAGER's prescribing is 21% brand-name and 79% generic drugs by claim count, with $660K in brand drug costs.
How many Physician Assistant providers are there in the US?
There are 149,975 Physician Assistant providers across 56 states in the US. The average Physician Assistant provider writes 790 Medicare Part D claims per year.
What drugs does WILLIAM SLAGER prescribe most often?
Based on 2023 Medicare Part D data, WILLIAM SLAGER's most frequently prescribed drugs include Lamotrigine, Levetiracetam, Aimovig Autoinjector. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does WILLIAM SLAGER accept Medicare?
WILLIAM SLAGER appears in CMS Medicare data with 1,568 Part D claims and 236 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify WILLIAM SLAGER's credentials?
WILLIAM SLAGER's NPI is 1902360605. 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.
Prescribing Data
CMS Medicare Part D Prescriber Public Use File (2023). Includes claims, drug costs, beneficiaries, and opioid prescribing rates.
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