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2026 NPPES data Radiation Oncology Physician NPI 1902955818 MD
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James Mason, MD

Radiation Oncology Physician in Wildomar, California.

This profile is drawn from the federal National Provider Identifier Registry (CMS NPPES), which lists more than 7 million U.S. healthcare providers - including 6,141 in Radiation Oncology Physician, and covers specialty classification, practice address, and Medicare Part D prescribing data when reported. According to CMS, every field reflects the provider's official federal registration, see our methodology.

Federal data, no proprietary rating. We show these CMS records as-is - no composite score, no star rating, no editorial opinion layered on top.
Prescribing volume
35
Medicare Part D claims · 21 beneficiaries · Radiation Oncology Physician avg: 135
MIPS score
99.1/100
▲ 16 pts above national avg 83.5 · Exceptional
Verify NPI on CMS Methodology
Compiled from official public sources by the editorial process.

What the federal data shows

James Mason, MD reported a CMS MIPS final score of 99.1/100 - above the 83.5 national average - and filed 35 Medicare Part D claims in 2024.

99.1/100
MIPS score · +16 vs avg
35
Part D claims, 2024
Likely
board-certified (heuristic)
≥91st
pct among measured MIPS (lower-bound band)

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.

Federal trust snapshot

What official records show about James Mason, MD

Federal records show an active NPI with both Medicare prescribing volume and a measured CMS quality score — objective registry data, not patient reviews.

  • Verified

    NPI registry status

    Active listing in the CMS National Provider Identifier Registry (NPI 1902955818), first enumerated 01/09/2007.

    Source: CMS NPPES

  • Reported

    Medicare Part D participation

    Filed 35 Medicare Part D prescription claims in the 2023 CMS public use file — indicates active Medicare prescribing participation.

    Source: CMS Part D Prescriber PUF

  • Reported

    CMS quality reporting (MIPS)

    Reported a CMS MIPS final score of 99.1/100 in the Quality Payment Program — a federal quality measure, not a patient review.

    Source: CMS Quality Payment Program

  • Reported

    Board certification signal

    Heuristic suggests board-certified status based on ABMS-eligible specialty taxonomy plus active CMS participation signals — not a direct ABMS verification.

    Source: NUCC taxonomy + CMS participation heuristic

  • Reported

    Hospital affiliations

    1 CMS Care Compare hospital affiliation on record — practice footprint from the Doctors and Clinicians file.

    Source: CMS Care Compare

  • State context

    State board disciplinary context

    California statewide board action statistics are published annually — these figures describe aggregate state activity, not James Mason, MD's individual license status. Verify directly with the state medical board.

    Source: MBC annual report 2023

  • Not in federal data

    Individual sanction lookup

    PlainDoctor does not publish per-provider disciplinary determinations. Confirm current license and any individual actions through the state medical board or FSMB verification service.

    Source: State medical board / FSMB

This trust snapshot summarizes only what appears in federal CMS/NPPES public records. It is not a composite score, star rating, patient review, or clinical recommendation. PlainDoctor never fabricates reviews or AggregateRating schema.

CMS NPPES provider registry desk

NPI 1902955818 · Radiation Oncology Physician

NPI-10 · ENUM-MID · TAX-MID · MIPS-ELITE · RX-TRACE · BOOK-LIGHT · PHOTO-FINISH

  • NPI-10 1902955818
  • ENUM-MID 2007
  • TAX-MID 6K Radiation Oncology
  • MIPS-ELITE 99.1/100
  • RX-TRACE 35
  • BOOK-LIGHT 643 in California
  • PHOTO-FINISH Pradip Amin, M.D. · ±0.1

MIPS final-score neighbourhood

Same-specialty nationwide peers by CMS final score, not geographic proximity

MIPS pts

What this shows Nearest measured MIPS peers for this NUCC specialty (2023 performance year).

Source CMS Quality Payment Program (MIPS) As of 2023

James Mason, MD's MIPS score vs every measured U.S. clinician

CMS Merit-based Incentive Payment System (MIPS) final score, 2023, the federal quality measure. Clinicians whose score CMS assigned without scoring any category are excluded.

99 ≥ 91st percentile 91% of 454,083 measured providers are in lower value bands

0–10: 8,684 measured providers (2%). Below this entry. 10–20: 3,008 measured providers (1%). Below this entry. 20–30: 3,069 measured providers (1%). Below this entry. 30–40: 2,746 measured providers (1%). Below this entry. 40–50: 2,928 measured providers (1%). Below this entry. 50–60: 5,882 measured providers (1%). Below this entry. 60–70: 13,906 measured providers (3%). Below this entry. 70–80: 94,570 measured providers (21%). Below this entry. 80–90: 129,887 measured providers (29%). Below this entry. 90+: 189,403 measured providers (42%). This entry sits in this band. This provider 0 100 every measured MIPS clinician, bucketed by value

Each bar is a band; taller bars hold more measured providers. 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.

The percentile is a conservative whole-score-point band: it counts only measured clinicians in lower score bands. A CMS MIPS metric is not a recommendation or a clinical-quality rating by PlainDoctor. See methodology § corpus placement.

Source CMS Merit-based Incentive Payment System (MIPS) · 2023

Where James Mason, MD sits

This provider among radiation oncology physician peers

Across the 1,834 radiation oncology physician providers who report both Medicare Part D prescribing and a MIPS quality score, James Mason, MD writes more Part D claims than 19% of them and scores higher on MIPS quality than 88% - placing this provider in the lower-volume, high-quality quadrant. Volume reflects patient-panel size and specialty, not quality; the two axes are independent.

Lower volume · High qualityHigh volume · High qualityLower volume · Lower qualityHigh volume · Lower quality0255075100023.146.269.392.4Part D claim volume, percentile in specialtyMIPS quality, percentilePoint, Part D claim volume, percentile in specialty: 73 · MIPS quality, percentile: 25Point, Part D claim volume, percentile in specialty: 88 · MIPS quality, percentile: 27Point, Part D claim volume, percentile in specialty: 50 · MIPS quality, percentile: 28Point, Part D claim volume, percentile in specialty: 75 · MIPS quality, percentile: 72Point, Part D claim volume, percentile in specialty: 80 · MIPS quality, percentile: 13Point, Part D claim volume, percentile in specialty: 40 · MIPS quality, percentile: 0Point, Part D claim volume, percentile in specialty: 55 · MIPS quality, percentile: 73Point, Part D claim volume, percentile in specialty: 65 · MIPS quality, percentile: 87Point, Part D claim volume, percentile in specialty: 57 · MIPS quality, percentile: 18Point, Part D claim volume, percentile in specialty: 38 · MIPS quality, percentile: 3Point, Part D claim volume, percentile in specialty: 3 · MIPS quality, percentile: 8Point, Part D claim volume, percentile in specialty: 87 · MIPS quality, percentile: 12Point, Part D claim volume, percentile in specialty: 58 · MIPS quality, percentile: 87Point, Part D claim volume, percentile in specialty: 32 · MIPS quality, percentile: 50Point, Part D claim volume, percentile in specialty: 17 · MIPS quality, percentile: 78Point, Part D claim volume, percentile in specialty: 10 · MIPS quality, percentile: 32Point, Part D claim volume, percentile in specialty: 27 · MIPS quality, percentile: 35Point, Part D claim volume, percentile in specialty: 85 · MIPS quality, percentile: 20Point, Part D claim volume, percentile in specialty: 77 · MIPS quality, percentile: 65Point, Part D claim volume, percentile in specialty: 60 · MIPS quality, percentile: 38Point, Part D claim volume, percentile in specialty: 52 · MIPS quality, percentile: 23Point, Part D claim volume, percentile in specialty: 3 · MIPS quality, percentile: 87Point, Part D claim volume, percentile in specialty: 42 · MIPS quality, percentile: 43Point, Part D claim volume, percentile in specialty: 22 · MIPS quality, percentile: 87Point, Part D claim volume, percentile in specialty: 28 · MIPS quality, percentile: 87Point, Part D claim volume, percentile in specialty: 13 · MIPS quality, percentile: 58Point, Part D claim volume, percentile in specialty: 90 · MIPS quality, percentile: 10Point, Part D claim volume, percentile in specialty: 82 · MIPS quality, percentile: 75Point, Part D claim volume, percentile in specialty: 78 · MIPS quality, percentile: 65Point, Part D claim volume, percentile in specialty: 48 · MIPS quality, percentile: 87Point, Part D claim volume, percentile in specialty: 18 · MIPS quality, percentile: 42Point, Part D claim volume, percentile in specialty: 98 · MIPS quality, percentile: 43Point, Part D claim volume, percentile in specialty: 97 · MIPS quality, percentile: 68Point, Part D claim volume, percentile in specialty: 23 · MIPS quality, percentile: 43Point, Part D claim volume, percentile in specialty: 37 · MIPS quality, percentile: 63Point, Part D claim volume, percentile in specialty: 92 · MIPS quality, percentile: 87Point, Part D claim volume, percentile in specialty: 70 · MIPS quality, percentile: 83Point, Part D claim volume, percentile in specialty: 42 · MIPS quality, percentile: 58Point, Part D claim volume, percentile in specialty: 100 · MIPS quality, percentile: 43Point, Part D claim volume, percentile in specialty: 7 · MIPS quality, percentile: 30Point, Part D claim volume, percentile in specialty: 72 · MIPS quality, percentile: 35Point, Part D claim volume, percentile in specialty: 68 · MIPS quality, percentile: 83Point, Part D claim volume, percentile in specialty: 67 · MIPS quality, percentile: 52Point, Part D claim volume, percentile in specialty: 83 · MIPS quality, percentile: 33Point, Part D claim volume, percentile in specialty: 20 · MIPS quality, percentile: 53Point, Part D claim volume, percentile in specialty: 93 · MIPS quality, percentile: 75Point, Part D claim volume, percentile in specialty: 63 · MIPS quality, percentile: 20Point, Part D claim volume, percentile in specialty: 53 · MIPS quality, percentile: 80Point, Part D claim volume, percentile in specialty: 32 · MIPS quality, percentile: 70Point, Part D claim volume, percentile in specialty: 30 · MIPS quality, percentile: 55Point, Part D claim volume, percentile in specialty: 8 · MIPS quality, percentile: 7Point, Part D claim volume, percentile in specialty: 25 · MIPS quality, percentile: 62Point, Part D claim volume, percentile in specialty: 45 · MIPS quality, percentile: 2Point, Part D claim volume, percentile in specialty: 12 · MIPS quality, percentile: 5Point, Part D claim volume, percentile in specialty: 47 · MIPS quality, percentile: 40Point, Part D claim volume, percentile in specialty: 2 · MIPS quality, percentile: 13Point, Part D claim volume, percentile in specialty: 0 · MIPS quality, percentile: 87Point, Part D claim volume, percentile in specialty: 35 · MIPS quality, percentile: 57Point, Part D claim volume, percentile in specialty: 95 · MIPS quality, percentile: 87Point, Part D claim volume, percentile in specialty: 60 · MIPS quality, percentile: 17James Mason, MD, Part D claim volume, percentile in specialty: 19 · MIPS quality, percentile: 88
Part D claim volume vs MIPS quality, by specialty percentile

Each dot is one radiation oncology physician peer from a representative sample of 60; the gold marker is James Mason, MD. Source: CMS Medicare Part D Prescriber data and the CMS Merit-based Incentive Payment System, 2023.

✓
Board certification likely (heuristic, not verified)

James Mason, MD practices in an ABMS-board-eligible specialty and shows active CMS Medicare participation + MIPS quality reporting + 1 hospital affiliation - signals consistent with board-certified status. For verified board certification, see CertificationMatters.org (the official ABMS public lookup).

What does the federal data show about James Mason, MD?

High performer (top quartile)

NPI registry status

Active

Issued 01/09/2007

NPI 1902955818

Primary specialty

Radiation Oncology Physician

Mid-sized

6,141 US NPIs in this specialty

Medicare Part D claims

35 74% vs specialty avg

2024 prescription claims

Specialty avg: 135

MIPS final score

99.1/100 15.6 pts vs avg

Exceptional band

vs 83.5 national avg

Specialty distribution in California

How Radiation Oncology Physician compares to other specialties among California providers

California providers
Behavior Technician17.9%Marriage & Family Therapist5.4%Student in an Organized Heal…5.1%Mental Health Counselor3.7%Pharmacist3.4%Clinical Social Worker3.1%Radiation Oncology Physician0.1%
Largest specialties in California (% of in-state providers)

Medicare quality performance, MIPS

James Mason, MD's 2023 MIPS final score plotted against the Radiation Oncology Physician national average

High performer (top quartile)
MIPS Final Score
99.1/100
vs 83.5 national avg · 2023 performance year
0%100%National avg84%99%
MIPS final score (Radiation Oncology Physician) - 99.1/100 vs national avg 83.5
How MIPS and board certification work

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).

Practice Address

36450 INLAND VALLEY DR
Wildomar, CA 92595
(951) 696-0679

Provider Details

NPI 1902955818
Specialty Radiation Oncology Physician
Credentials MD
Gender Male
NPI Issued 01/09/2007

CMS Quality Score (MIPS)

Merit-based Incentive Payment System (MIPS) scores from CMS, 2023 performance year.

99.1275
Final Score
Measured-score avg: 83.5
85.2396
Quality
100
Promoting Interoperability

Reporting: Group practice

Hospital and facility affiliations

Facilities where James Mason, MD 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.

City OF Hope Medical Foundation
Wildomar, CA

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

License & disciplinary context - California MBC 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 ~150K California medical licensees in 2023 - they are NOT specific to James Mason, MD. To verify James Mason, MD's current license status, search the MBC public license lookup directly, or check the Federation of State Medical Boards (FSMB) verification service.

576
Total board actions, California 2023
Across 556 cases
3.84
Actions per 1,000 licensees
California statewide rate
probation
Most common action type
186 cases

MBC 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 California disciplinary trends page. Cross-checked against FSMB U.S. Medical Regulatory Trends.

Medicare Part D Prescribing Data

CMS Medicare Part D prescriber-level data for calendar year 2024.

35
Total Claims
$484
Total Drug Cost
21
Medicare Beneficiaries

Prescribing Breakdown

30-Day Fills
39.667
Total Day Supply
822
Generic Drug Cost
$435

Patient Demographics

Average Patient Age
71.6 years
Avg HCC Risk Score
2.83
More Radiation Oncology Physician in CA → All providers in California → Compare specialties →

Radiation Oncology Physician Overview

How James Mason, MD fits within the Radiation Oncology Physician landscape nationally.

6,141
Radiation Oncology Physician Providers in US
53
States with Radiation Oncology Physician
135
Avg Claims per Provider

James Mason, MD's 35 claims are below the specialty average of 135.

Nationwide Radiation Oncology Physician peers with similar MIPS or enrollment year

Two federal-record peer sets for Mason, both outside California so the neighborhoods are not geographic containment.

Similar MIPS final score

Nearest same-specialty clinicians by CMS MIPS final score (99.1 here).

Pradip Amin 99.2 MD Rashmi Benda 99.2 RI Dhananjay Bendre 99.2 FL Joseph Cirrone 99.2 NY

Same NPPES enumeration year (2007)

Same-specialty clinicians who entered the NPI registry in the same calendar year, outside this state.

Jergin Chen Salt Lake City, UT Ryan Steinmetz Middletown, OH Niloyjyoti Deb Temple, TX Eddy Yang Lexington, KY

Nearby Radiation Oncology Physician Providers in California

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

One of 643 Radiation Oncology Physician providers enrolled in California, 5 are shown here.

Christina Abel
NURSE PRACTITIONER
Orange, CA
Dr. Roy Abendroth
MD
San Francisco, CA
Dr. Sunil Advani
M.D.
La Jolla, CA
Dr. Faisal Ahmed
MD
Stanford, CA
Dr. Eugene Ahn
MD
Simi Valley, CA

Compare Radiation Oncology Physician nationally: see state-by-state distribution →

Frequently Asked Questions

What is James Mason, MD's specialty? ▼
James Mason, MD specializes in Radiation Oncology Physician and practices in Wildomar, California. Credentials: MD.
How much does James Mason, MD prescribe under Medicare Part D? ▼
In 2024, James Mason, MD wrote 35 Medicare Part D claims totaling $484 in drug costs for 21 beneficiaries.
What is James Mason, MD's Medicare quality score? ▼
James Mason, MD has a CMS MIPS Final Score of 99.1/100 (Quality: 85.2). The average MIPS Final Score across the 454,083 clinicians with at least one published category score is 83.5; clinicians whose score CMS assigned without scoring any category are excluded from that average. Source: CMS Merit-based Incentive Payment System (MIPS) 2023.
Where is James Mason, MD located? ▼
James Mason, MD is located at 36450 INLAND VALLEY DR, Wildomar, CA, 92595. Phone: (951) 696-0679.
What is James Mason, MD's NPI number? ▼
James Mason, MD's National Provider Identifier (NPI) is 1902955818, issued on 01/09/2007.
How many Radiation Oncology Physician providers are there in the US? ▼
There are 6,141 Radiation Oncology Physician providers across 53 states in the US. The average Radiation Oncology Physician provider writes 135 Medicare Part D claims per year.
Does James Mason, MD accept Medicare? ▼
James Mason, MD appears in CMS Medicare data with 35 Part D claims and 21 Medicare beneficiaries in 2024. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify James Mason, MD's credentials? ▼
James Mason, MD's NPI is 1902955818 with credentials MD. 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

View source datasets and methodology notes
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 (2024). Includes claims, drug costs, beneficiaries, and opioid prescribing rates.
Quality Performance
CMS Merit-based Incentive Payment System (MIPS) - 2023 performance year.
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 August 2026 (NPPES) / 2024 (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

Compiled from official public sources by the editorial process.

Every figure on PlainDoctor is rendered directly from the federal CMS NPPES registry, Medicare Part D, MIPS, and Open Payments records, no number is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of August 2026.