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Medicaid Statistical Information Statistics (MSIS)

Prior to Federal fiscal year 1999, the Medical Statistical Information System (MSIS) was a voluntary program and those states participating in the MSIS project provided data tapes from their claims processing systems to the Centers for Medicare & Medicaid Services (CMS) in lieu of the hard-copy statistical 2082 tables. However, in accordance with the Balanced Budget Act (BBA) of 1997, all claims processed are submitted electronically through MSIS. Important crosswalk instructions are described in the State Participation Procedures Manual (see the link in the "Downloads" section below).

The State Participation Procedures Manual, including instructions for eligibility and claims crosswalks is in zipped Word format (see "Downloads" section below)

The MSIS Tape Specification and Data Dictionary contains instructions on the file submissions. These files must meet the specifications outlined in the MSIS Tape Specification and Data Dictionary. The MSIS Tape Specification and Data Dictionary can be downloaded Adobe Acrobat (PDF) formats. (see link in the "Downloads" section below)

Release 3.1, effective for files submitted ON or AFTER February 15, 2009, provides information for the expansion of all four MSIS claims files to collect the National Provider ID (NPI), the provider taxonomy code and claims internal control numbers (ICN).  In addition, filler space has been added for future data needs.  The current version  updates references to the Child Health Insurance Program (CHIP).

This release also includes directions for data encryption for all files and instructions for electronic file transfer.

The MSIS Tape Specification and Data Dictionary (Release 3.1) file (msisdd20010.pdf - 735KB) is in Adobe Acrobat format. (Note: This file requires the Adobe Acrobat Reader software in order to view.) 

To view important MSIS clarifying information concerning file record sizing, data set naming conventions, labeling, and volume/serial requirements is available by clicking on the "MSIS Submission Format" link on the left-side column. This information needs to be read prior to submitting MSIS tapes. All MSIS tape submittals must conform to the requirements described in this document. Failure to conform to any of these requirements will result in MSIS tapes being returned unprocessed.

MSIS data are used by CMS to produce Medicaid program characteristics and utilization information for those states. These data also provide CMS with a large-scale database of state eligibles and services for other analyses. The purpose of MSIS is to collect, manage, analyze and disseminate information on eligibles, beneficiaries, utilization and payment for services covered by State Medicaid programs. States provide CMS with quarterly computer files containing specified data elements for: (1) persons covered by Medicaid (Eligible files); and, (2) adjudicated claims (Paid Claims files) for medical services reimbursed with Title XIX funds. These data are furnished on the Federal fiscal year quarterly schedule, which begins October 1 of each year.

Each state eligible file contains one record for each person covered by Medicaid for at least one day during the reporting quarter. Individual eligible records consist of demographic and monthly enrollment data. Paid claims files contain information from adjudicated medical service related claims and capitation payments. Four types of claims files representing inpatient, long term care, prescription drugs and noninstitutional services are submitted by the states. These are claims that have completed the state's payment processing cycle for which the state has determined it has a liability to reimburse the provider from Title XIX funds. Claims records contain information on the types of services provided, providers of services, service dates, costs, types of reimbursement, and epidemiological variables.

The data files are subjected to quality assurance edits to ensure that the data are within acceptable error tolerances and a distributional review verifies the reasonableness of the data. Once accepted, valid tape files are created which serve as the historical source of detailed Medicaid eligibility and paid claims data maintained by CMS. The individual paid claims and eligible information are used for program analysis and research and to produce various public use reports which represent national Medicaid populations and expenditures.

The current uses of MSIS data include

  • health care research and evaluation activities;
  • program utilization and expenditures forecasting;
  • analyses of policy alternatives;
  • responses to congressional inquiries; and
  • matches to other health related databases.