Data Sources

CMS Hospital Price Transparency Files

Since January 2021, CMS requires all Medicare-certified hospitals to publish their negotiated rates in machine-readable format. The V3.0 specification (effective January 2024) standardizes the file schema, making cross-hospital comparison computationally feasible for the first time.

We ingest and normalize these files into a unified schema. Each rate record is stored with its source hospital, payer, plan type, billing code, and effective date. Rates that cannot be validated against the CMS code registry are flagged and excluded from percentile calculations.

CMS Physician Fee Schedule (PFS)

The PFS establishes the Medicare-allowed amount for every CPT code based on Relative Value Units. We use this as the pricing floor and geographic baseline.

• Publisher: Centers for Medicare & Medicaid Services
• URL: cms.gov/medicare/payment/fee-schedules/physician
• Update Frequency: Annual (final rule each November, effective January)
• Key Fields: CPT/HCPCS code, Work RVU, PE RVU (facility/non-facility), MP RVU, conversion factor, status indicator

CMS OPPS & IPPS Fee Schedules

The Outpatient Prospective Payment System (OPPS) governs facility fees for outpatient hospital services. The Inpatient Prospective Payment System (IPPS) governs inpatient hospital payments via MS-DRG (Medicare Severity Diagnosis Related Groups).

• OPPS Addendum B: APC (Ambulatory Payment Classification) rates for every outpatient procedure code
• IPPS Impact File: MS-DRG weights, wage indices, and hospital-specific payment rates
• ASC Payment System: Separate facility fee schedule for procedures performed in ambulatory surgery centers

CMS Hospital Compare

The quality dimensions of our QACS score draw entirely from CMS Hospital Compare, which aggregates quality metrics for every Medicare-certified hospital.

• Overall Star Ratings: 1-5 star composite across 7 quality domains
• HCAHPS: Patient experience survey results (communication, responsiveness, cleanliness, discharge info, overall rating)
• Outcomes: 30-day mortality, readmission, and complication rates by condition and procedure
• Safety: Healthcare-associated infection rates, patient safety indicators
• Update Frequency: Quarterly refreshes on data.cms.gov

CMS GPCI (Geographic Practice Cost Index)

GPCIs adjust the national fee schedule for local cost differences. We use them to normalize prices across regions and compute the Price Fairness Index.

• Coverage: 112 Medicare payment localities
• Components: Work GPCI, Practice Expense GPCI, Malpractice GPCI
• Source: Published as part of the annual PFS final rule
• Application: Multiplied against corresponding RVU components to produce locality-adjusted rates

NPPES (National Plan and Provider Enumeration System)

NPPES is the registry for all NPI (National Provider Identifier) numbers. We use it to link facilities and physicians to their transparency file data and to populate facility profiles.

• Coverage: 7.8M+ provider records (individuals and organizations)
• Key Fields: NPI, legal name, practice address, taxonomy (specialty), organization affiliations
• Update Frequency: Monthly NPI data dissemination file

BLS Medical CPI

The Bureau of Labor Statistics publishes Consumer Price Index data for medical care services by metropolitan statistical area. We use this to:

• Calibrate commercial price expectations in areas with limited transparency data
• Track year-over-year medical cost inflation by region
• Validate that our commercial multiplier estimates align with observed price trends

Series: CUUR0000SAM (US city average, medical care services) and regional variants. Updated monthly.

KFF Employer Health Benefits Survey

The Kaiser Family Foundation conducts an annual survey of employer-sponsored health insurance that provides critical benchmark data:

• Average premiums by plan type (HDHP, PPO, HMO, POS) and region
• Average deductible and OOP maximum by plan type
• Coinsurance rates and copay structures
• Employer vs. employee premium contribution shares

We use KFF data to power our default plan design assumptions when users do not input their specific plan parameters, ensuring OOP estimates are grounded in real market data.

ACA Marketplace Premium Data

CMS publishes ACA marketplace plan data annually through the Public Use Files (PUFs), covering every plan sold on HealthCare.gov and state-based exchanges.

• Plan Attributes PUF: Metal level, plan type, issuer, deductible, OOP max, coinsurance rates
• Rate PUF: Monthly premiums by rating area, age, tobacco status
• Coverage: All 50 states + DC, every certified QHP
• Update Frequency: Annual (open enrollment data published each fall)

For users on ACA marketplace plans, we can match their specific plan to our database and pre-populate all benefit design parameters for instant OOP estimation.

Data Freshness and Quality

We track the last-updated timestamp for every data source and display data freshness indicators in the API response. Our data pipeline runs the following schedule:

• Transparency files: Quarterly re-ingestion with delta detection
• PFS/OPPS/IPPS: Annual update upon CMS final rule publication
• Hospital Compare: Quarterly sync with data.cms.gov
• NPPES: Monthly NPI file refresh
• BLS Medical CPI: Monthly series update
• KFF/ACA: Annual upon publication

No synthetic or fabricated data is used anywhere in the system. Where source data is missing or incomplete, we flag it as such rather than imputing values. Thedata_sources table in our D1 database tracks the provenance, last sync timestamp, and row count for every ingested dataset.