MAX Provider Charisteristics File (MAXPC): Linking to Medicare Provider Numbers


This article outlines the provider identification numbers that are available in the MAX files and options for linking to the Medicare Provider Number.

Current Version Date:

Medicaid Analytic Extract (MAX) files prior to 2009 identify providers by state-specific identification codes. The National Provider ID (NPI) was added to the files in 2009. The following table details the provider numbers variables in each file pre- and post- 2009.

MAX File/Variable Name File pre-2009 File post-2009
Billing Provider ID (legacy/state) IP IP
Servicing Provider ID (legacy/state) OT OT
Prescribing Provider ID (legacy/state) RX RX
National Provider NPI IP (billing institution)
LT (billing institution)
RX (billing provider)
OT (servicing provider)
Provider Taxonomy (NPI based code) IP (billing provider)
LT (billing provider)
RX (billing provider)
OT (servicing provider)
Prescribing Physician ID (state/DEA) RX RX

Different states populate these variables at different rates across the years. There are two resources which assess the amount of data available for any these variables. Prior to requesting MAX files, researchers should consult the MAX Data Validation Tables and the MAXPC file. In some cases, states have submitted NPIs in fields which are defined as containing a legacy ID. The resources will identify the frequency of this occurrence by state/year/file.

The MAX Data Validation Tables are created after MAX production is complete for a calendar year. There is one Excel workbook for each state. They are created to cover three years, so that data can easily be viewed for a specific measure across time. For each utilization file, the percent of claims that include an NPI is documented, along with the percent of NPIs that are reported for one of the available provider identification fields. Eg: in the MAX OT file, the percent of NPIs reported for billing or servicing provider is reported. The MAX Validation Tables also include the percent of claims which report a value for the national provider taxonomy. Previously, the reported specialty code was state-specific and the descriptions were not available in the MAX data.

The MAXPC file was created for states with available data, 2009-2011. In 2009, all 50 states and DC were available. For 2010, the total is 45 jurisdictions and 35 for 2011. Data is pulled from the National Plan and Provider Enumeration System (NPPES) and available state-specific provider files. The goal of the file development was to provide easily linkable information on providers found in the MAX files. Documentation includes SAS load statements, data dictionaries, state-specific validation tales, cross-state validation tables, specifications for these validation elements and anomaly tales. The cross-state tables make it easy to compare data collected by individual states and assess how it could affect analysis for studies where provider information is important. Linkage rates to the NPPES are also provided. The evaluation report gives an assessment of states’ reporting and whether the data quality supports research.

The legacy state-specific ID can be linked to the NPI through the data provided in the MAX Provider Characteristics file, MAX PC. Linkage is limited by the data each state made available in their MAX data. Completion rates for the NPI field varies by year, state and utilization file type.

Please see the MAXPC data documentation for specifics on file creation. The database is available as a download from the CMS MAXPC website.