WILLIAM CLARK
Medical Physician Assistant in PRESCOTT, Arizona. CMS National Plan and Provider Enumeration System profile including specialty classification, practice address, and Medicare prescribing data when reported.
What the federal data shows
WILLIAM CLARK filed 576 Medicare Part D claims in 2023 as a Medical Physician Assistant in PRESCOTT, Arizona, prescribing 92% generic.
- 576
- Part D claims, 2023
- 92%
- generic prescribing
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 CLARK's Medicare Part D volume vs every U.S. prescriber
Total Medicare Part D claims, 2023 — across all CMS prescribers nationally
576 Top 34% higher than 66% of 1,370,886 prescribers
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 CLARK?
Quality data not reportedPrimary specialty
Medicare Part D claims
Specialty distribution in Arizona
How Medical Physician Assistant compares to other specialties among Arizona providers
Medical Physician Assistant share within Arizona
Medical Physician Assistant is one of the more visible NUCC categories in Arizona
Each bar reflects the share of in-state providers whose primary NUCC taxonomy matches the specialty. Long tail of ~690 NUCC codes folded into "Other" to keep the comparison legible.
Specialty board-certification context
Estimated specialty board-certified rate — Medical Physician Assistant (ABMS / AOA reference)
- Est. board-certified rate
- 78%
- Medical Physician Assistant ABMS/AOA estimate
Est. board-certified rate (Medical Physician Assistant) — ABMS / AOA estimate
Verify credentials
- Verify via ABMS free public lookup
- Verify via AOA osteopathic boards
- Specialty volume Medical Physician Assistant US NPIs
Specialty board-certified rate — Medical Physician Assistant estimate
Board certification through an ABMS or AOA member board signals voluntary post-licensure examination plus Maintenance of Certification cycles. CMS does not publish a per-provider board-certification field; the figure shown is the specialty-level estimated rate from ABMS / AOA reference data.
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 CLARK appears in the CMS NPPES registry as a Medical Physician Assistant provider at 1042 WILLOW CREEK RD, PRESCOTT, AZ, 86301, with a listed phone of (928) 379-0838. NPI 1184362659 was issued on 05/24/2022. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what CLARK 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 576 prescription claims written by this provider, covering 404 Medicare beneficiaries and totaling roughly $12K in drug spend, split 8% brand-name and 92% generic by claim count, with an opioid prescribing rate of 19.3%. 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.
Medical Physician Assistant is a mid-sized specialty nationwide, with 40,527 enrolled providers across 55 states and an average of 1,077 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
Provider Details
| NPI | 1184362659 |
|---|---|
| Specialty | Medical Physician Assistant |
| Gender | Male |
| NPI Issued | 05/24/2022 |
Verify this provider's license
PlainDoctor pulls this profile from the CMS NPPES public registry. Confirm WILLIAM CLARK's current license status, disciplinary history, and board certifications with the Arizona Medical Board in Arizona before relying on this page for a clinical or care decision.
How we sourced this profile
Brand vs generic prescribing mix · Generic-heavy
8% brand-name claims vs 92% generic, on 576 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.
Prescribing Breakdown
- 30-Day Fills
- 631
- Total Day Supply
- 7,078
- Brand vs Generic
- 8% brand / 92% generic
- Brand Drug Cost
- $8K
- Generic Drug Cost
- $4K
- Opioid Claims
- 111 (19.3% rate)
- Antibiotic Claims
- 189
Patient Demographics
- Average Patient Age
- 72.9 years
- Avg HCC Risk Score
- 1.33
- Gender Split
- 62% female / 38% male
- Age Distribution
- <65: 58, 65-74: 170, 75-84: 125, 85+: 51
Top Prescribed Drugs (Medicare Part D)
Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.
What WILLIAM CLARK prescribes most
Top Medicare Part D drugs by claim count, 2023
- Hydrocodone-Acetam…
Hydrocodone-Acetaminophen
84 claims
- Cephalexin
Cephalexin
66 claims
- Prednisone
Prednisone
38 claims
- Ondansetron Hcl 24
Ondansetron Hcl
24 claims
- Amoxicillin-Clavul… 23
Amoxicillin-Clavulanate Potass
23 claims
- Albuterol Sulfate … 22
Albuterol Sulfate Hfa
22 claims
- Azithromycin 19
Azithromycin
19 claims
- Ciprofloxacin Hcl 16
Ciprofloxacin Hcl
16 claims
| Drug | Claims |
|---|---|
| Hydrocodone-Acetaminophen Hydrocodone/Acetaminophen | 84 |
| Cephalexin | 66 |
| Prednisone | 38 |
| Ondansetron Hcl | 24 |
| Amoxicillin-Clavulanate Potass Amoxicillin/Potassium Clav | 23 |
| Albuterol Sulfate Hfa Albuterol Sulfate | 22 |
| Azithromycin | 19 |
| Ciprofloxacin Hcl | 16 |
| Methylprednisolone | 15 |
| Diclofenac Sodium | 14 |
* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.
Medical Physician Assistant Overview
How WILLIAM CLARK fits within the Medical Physician Assistant landscape nationally.
WILLIAM CLARK's 576 claims are below the specialty average of 1,077.
Nearby Medical Physician Assistant Providers in Arizona
Other clinicians with the same primary specialty enrolled in Arizona, drawn from the same CMS NPPES roster as CLARK.
Compare Medical Physician Assistant nationally: see state-by-state distribution →
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Frequently Asked Questions
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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