Task 1: CMS Medicaid data content

This task will provide a description of the contents of the NHANES files linked to Medicaid eligibility and service utilization Medicaid Analytic eXtract (MAX) data files.  The structure of the data files is described in Course 1, Module 1.

Diagram: NHANES-Medicaid Linked Data Structure

Diagram of Medicaid File Structure
View text version of Diagram


File descriptions and contents

Enrollment & Summary Files

Person Summary File

The Person Summary (PS) File includes person level data on eligibility, demographics, basis of eligibility, managed care enrollment, a summary of utilization and Medicaid payment by type of service.   The file contains one record for every individual enrolled for at least one day during the year. 

information icon Information

You should always include a request for the Person Summary (PS) File as part of your data request. Although the PS File contains gender, race, and date of birth variables, NCHS recommends that you use gender, race-ethnicity and date of birth provided by NHANES.

Claims Files

Inpatient Hospital File

The Inpatient Hospitalization (IP) File contains complete stay records for Medicaid enrollees who used inpatient services including diagnoses, procedures, discharge status, length of stay, and payment amount. Users will find up to ten diagnosis code fields and seven procedure fields.

Other Services File

The Other Services (OT) File contains claim records for all non-institutional Medicaid services, including physician services, lab/x-ray, clinic services and premium payments. Each claim record includes diagnosis, procedure and date of service.

Long Term Care File

The Long Term Care (LT) File contains claims for long term care services provided by Skilled Nursing Facilities (SNF), Intermediate Care Facilities (ICFs), and independent psychiatric facilities. Each claim record contains facility type, dates of service, and discharge status.  There is one diagnostic code variable, but no procedure code variables on the Long Term Care File. 

Prescription Drug File

The Prescription Drug (RX) File contains claims for paid drug prescriptions.  The National Drug Code is used for identification of each drug product.  The Prescription Drug File contains one procedure code variable, but no diagnosis codes.  Drugs provided during an inpatient stay are not available.  Injectable drugs administered by a health care professional are included in the OT file.

Variable lists and Record Layouts

A full list of the variables for the NCHS-CMS Medicaid files [insert link to] is available on the NCHS website.

Common variables

In addition to the NHANES participant public use ID (variable name: SEQN), there are several other common types of variables which appear in the different Medicaid data files. Examples include diagnoses associated with the visit, dates of service, provider type, charges and costs. There is also some demographic information on all files.

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The Medicaid data come from administrative records and there may be some inconsistencies because Medicaid data are collected for administrative, not research purposes.



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