CMS Data Dictionary References

For detailed documentation on the column names, coding schemes, and file layouts used in Medicaid claims data, refer to the official CMS and ResDAC resources below.

Medicaid Claims File Documentation

Resource

URL

MAX General Information (ResDAC)

https://resdac.org/cms-data/files/max-ip

TAF Documentation (ResDAC)

https://resdac.org/cms-data/files/taf-ip

TAF Research Variables (ResDAC)

https://resdac.org/

ResDAC Data Documentation

https://resdac.org/

Geographic Classification

Classification

URL

RUCA (Rural-Urban Commuting Area)

https://www.ers.usda.gov/data-products/rural-urban-commuting-area-codes/

RUCC (Rural-Urban Continuum Codes)

https://www.ers.usda.gov/data-products/rural-urban-continuum-codes/

FIPS County Codes

https://www.census.gov/library/reference/code-lists/ansi.html

SSA State/County Codes

https://www.nber.org/research/data/ssa-federal-information-processing-series-fips-state-and-county-crosswalk

Provider Data

Dataset

URL

NPI Registry

https://npiregistry.cms.hhs.gov/

NPPES Data Dissemination

https://download.cms.gov/nppes/NPI_Files.html

HCRIS (Cost Reports)

https://www.cms.gov/Research-Statistics-Data-and-Systems/Downloadable-Public-Use-Files/Cost-Reports

UDS (Uniform Data System)

https://data.hrsa.gov/tools/data-reporting/program-data

Provider of Services (POS)

https://data.cms.gov/provider-characteristics/hospitals-and-other-facilities/provider-of-services-file-hospital-non-hospital-facilities

Column Name Conventions

MAX files use column names like:

  • DIAG_CD_1 through DIAG_CD_9 – diagnosis codes

  • PRCDR_CD_1 through PRCDR_CD_6 – procedure codes

  • PRCDR_CD_SYS_1 through PRCDR_CD_SYS_6 – procedure coding system (1=CPT, 6=ICD-9, 7=ICD-10-PCS)

  • SRVC_BGN_DT, SRVC_END_DT – service dates

  • ADMSN_DT, DSCHRG_DT – admission/discharge dates (IP)

  • RCPNT_DLVRY_CD – delivery recipient code

TAF files use column names like:

  • DGNS_CD_1 through DGNS_CD_12 – diagnosis codes

  • ADMTG_DGNS_CD – admitting diagnosis

  • PRCDR_CD_1 through PRCDR_CD_6 – procedure codes

  • LINE_PRCDR_CD – line-level procedure code

  • SRVC_BGN_DT, SRVC_END_DT – service dates

  • NDC – National Drug Code (pharmacy claims)

  • DAYS_SUPPLY – prescription days of supply

The package automatically detects MAX vs TAF column naming conventions based on the cms_format parameter ("MAX" or "TAF").