NPI registry status
Active
2026 NPPES data Obstetrics & Gynecology Physician NPI 1477526028 DO
Verify on CMS → Ralph Armstrong, DO
Obstetrics & Gynecology Physician in Hollister, 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 44,326 in Obstetrics & Gynecology 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
134
Medicare Part D claims · 46 beneficiaries · Obstetrics & Gynecology Physician avg: 179
Generic prescribing
81%
generic claims · 19% brand-name · higher generic rates reduce patient out-of-pocket costs
Industry payments
$171.77
13 payments · CMS Open Payments (Sunshine Act)
Source: CMS Medicare Part D Prescriber Public Use File, 2023
Compiled from official public sources by the PlainDoctor editorial team.
What the federal data shows
Ralph Armstrong, DO filed 134 Medicare Part D claims in 2023 as a Obstetrics & Gynecology Physician in Hollister, California, prescribing 81% generic.
- 134
- Part D claims, 2023
- 81%
- generic prescribing
- Likely
- board-certified (heuristic)
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.
Ralph Armstrong, DO's Medicare Part D volume vs every U.S. prescriber
Total Medicare Part D claims, 2023, across all CMS prescribers nationally
134 35th percentile higher than 35% 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
✓
Board certification likely (heuristic, not verified)
Ralph Armstrong, DO practices in an ABMS-board-eligible specialty and shows active CMS Medicare participation + 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 Ralph Armstrong, DO?
Quality data not reportedPrimary specialty
Obstetrics & Gynecology Physician
Medicare Part D claims
134 25% vs specialty avg
Specialty distribution in California
How Obstetrics & Gynecology Physician compares to other specialties among California providers
Board certification
Not published by CMS
CMS does not publish a per-provider board-certification field in NPPES. PlainDoctor does not have a reliable per-specialty certification rate to show for Obstetrics & Gynecology Physician. Verify directly:
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).
Ralph Armstrong, DO appears in the CMS NPPES registry as a Obstetrics & Gynecology Physician provider holding DO credentials at 931 SUNSET DR, Hollister, CA, 95023, with a listed phone of (831) 635-0604. NPI 1477526028 was issued on 02/13/2006.
Medicare Part D records for calendar year 2023 show 134 prescription claims written by this provider, covering 46 Medicare beneficiaries and totaling roughly $12K in drug spend, split 19% brand-name and 81% generic by claim count.
Obstetrics & Gynecology Physician is a mid-sized specialty nationwide, with 44,326 enrolled providers across 56 states and an average of 179 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 | 1477526028 |
|---|---|
| Specialty | Obstetrics & Gynecology Physician |
| Credentials | DO |
| Gender | Male |
| NPI Issued | 02/13/2006 |
Hospital and facility affiliations
Facilities where Ralph Armstrong, DO 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.
Obstetrix Medical Group OF California A Professional Corporation
San Jose, 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).
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 Ralph Armstrong, DO. Source: openpaymentsdata.cms.gov.
Total received
$172
Largest payer
MAYNE PHARMA COMMERCIAL 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 - 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 Ralph Armstrong, DO. To verify Ralph Armstrong, DO'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.
Brand vs generic prescribing mix · Typical
Ralph Armstrong, DO - brand share 19.0%
Obstetrics & Gynecology Physician average
19% brand-name claims vs 81% generic, on 134 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.
134
Total Claims
$12K
Total Drug Cost
46
Medicare Beneficiaries
Prescribing Breakdown
- 30-Day Fills
- 200
- Total Day Supply
- 5,032
- Brand vs Generic
- 19% brand / 81% generic
- Brand Drug Cost
- $8K
- Generic Drug Cost
- $4K
- Antibiotic Claims
- 20
Patient Demographics
- Average Patient Age
- 68.9 years
- Avg HCC Risk Score
- 0.83
- Gender Split
- 100% female / 0% male
Top Prescribed Drugs (Medicare Part D)
Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.
What Ralph Armstrong, DO prescribes most
Top Medicare Part D drugs by claim count, 2023
- Imvexxy
Imvexxy
14 claims
- Lidocaine
Lidocaine
13 claims
- Clobetasol Propion…
Clobetasol Propionate
11 claims
| Drug | Claims |
|---|---|
| Imvexxy Estradiol | 14 |
| Lidocaine | 13 |
| Clobetasol Propionate | 11 |
* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.
Obstetrics & Gynecology Physician Overview
How Ralph Armstrong, DO fits within the Obstetrics & Gynecology Physician landscape nationally.
44,326
Obstetrics & Gynecology Physician Providers in US
56
States with Obstetrics & Gynecology Physician
179
Avg Claims per Provider
Ralph Armstrong, DO's 134 claims are below the specialty average of 179.
Nearby Obstetrics & Gynecology Physician Providers in California
Other clinicians with the same primary specialty enrolled in California, drawn from the same CMS NPPES roster as Armstrong.
Dr. Ingrid Aalami
MD
San Jose, CA
Dr. Avisa Abaian- Eagar
M.D.
Orange, CA
Dr. Derek Abbassi
MD
Walnut Creek, CA
Dr. Nicole Abell
DO
Ventura, CA
Zachary Abelson
Los Angeles, CA
Compare Obstetrics & Gynecology Physician nationally: see state-by-state distribution →
Before you book an appointment
Use this federal record as your verification checklist, not as a recommendation.
- Confirm the NPI record is current in the official CMS registry, providers update their own NPPES details, and moves can lag. Verify this NPI
- Check the active license and any disciplinary history with the California medical board, federal registration is not a license check. Credential verification guide
- Weigh a second option: compare this provider with a nearby Obstetrics & Gynecology Physician peer on Medicare volume and prescribing patterns. Compare providers
Medicare Part D and MIPS figures describe practice patterns in federal programs only, they are not quality ratings, and PlainDoctor does not rate, rank, or recommend providers.
Healthcare Guides
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Frequently Asked Questions
What is Ralph Armstrong, DO's specialty? ▼
Ralph Armstrong, DO specializes in Obstetrics & Gynecology Physician and practices in Hollister, California. Credentials: DO.
How much does Ralph Armstrong, DO prescribe under Medicare Part D? ▼
In 2023, Ralph Armstrong, DO wrote 134 Medicare Part D claims totaling $12K in drug costs for 46 beneficiaries.
Where is Ralph Armstrong, DO located? ▼
Ralph Armstrong, DO is located at 931 SUNSET DR, Hollister, CA, 95023. Phone: (831) 635-0604.
What is Ralph Armstrong, DO's NPI number? ▼
Ralph Armstrong, DO's National Provider Identifier (NPI) is 1477526028, issued on 02/13/2006.
Does Ralph Armstrong, DO prescribe more brand-name or generic drugs? ▼
Ralph Armstrong, DO's prescribing is 19% brand-name and 81% generic drugs by claim count, with $8K in brand drug costs.
How many Obstetrics & Gynecology Physician providers are there in the US? ▼
There are 44,326 Obstetrics & Gynecology Physician providers across 56 states in the US. The average Obstetrics & Gynecology Physician provider writes 179 Medicare Part D claims per year.
What drugs does Ralph Armstrong, DO prescribe most often? ▼
Based on 2023 Medicare Part D data, Ralph Armstrong, DO's most frequently prescribed drugs include Imvexxy, Lidocaine, Clobetasol Propionate. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Ralph Armstrong, DO accept Medicare? ▼
Ralph Armstrong, DO appears in CMS Medicare data with 134 Part D claims and 46 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Ralph Armstrong, DO's credentials? ▼
Ralph Armstrong, DO's NPI is 1477526028 with credentials DO. 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 (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
Compiled from official public sources by the PlainDoctor editorial team.