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Reporting ENROLLMENT-TYPE for CHIP Populations in the Eligible File (Eligibility)

Brief Issue Description

This best practice document outlines the challenges states have faced when reporting ENROLLMENT-TYPE for their Children's Health Insurance Program (CHIP) populations in the Transformed Medicaid Statistical Information System (T-MSIS) Eligible file record segment ENROLLMENT-TIME-SPAN-SEGMENT-ELG00021 and recommends best practices for states' reporting.

Background Discussion


The data element ENROLLMENT-TYPE data element distinguishes between an individual's enrollment in Medicaid or CHIP, and states are required to submit the record segment ENROLLMENT-TIME-SPAN-SEGMENT-ELG00021 for every enrolled individual. The eligible record segment VARIABLE-DEMOGRAPHICS-ELIGIBILITY-ELG00003 contains the CHIP-CODE data element where a state is able to further specify the types of CHIP enrollment the individual possesses for the timeframe specified in record segment ELG00021.1


When states are reporting CHIP enrollment, there have been instances where the ENROLLMENT-TYPE and CHIP-CODE do not correctly correspond to one another. Clarification is also needed on whether Medicaid Expansion CHIP populations should be reported with an ENROLLMENT-TYPE of Medicaid or CHIP. ENROLLMENT-TYPE must be coded appropriately for CMS to clearly determine whether an individual is enrolled in either Medicaid or CHIP programs. 

CMS Guidance

States should revisit how they are populating both CHIP-CODE and ENROLLMENT-TYPE to resolve inconsistencies in their mapping. The following list describes how states should classify enrollment for their CHIP population across these data elements:

  • If an individual is enrolled in a Medicaid Expansion CHIP, then his or her CHIP-CODE should be "2" and ENROLLMENT-TYPE should be "1" (Medicaid).
  • If an individual is not enrolled in a Medicaid Expansion CHIP and is included in a separate Title XXI CHIP program, then his or her CHIP-CODE should be "3" and ENROLLMENT-TYPE should be "2" (CHIP).
  • An unknown ENROLLMENT-TYPE ("9") should not be used.

When a state submits enrollment record segments it should update both data elements to reflect changes to enrollment classification for applicable time periods. CHIP-CODE is an enrollment data element that is included on the VARIABLE-DEMOGRAPHICS-ELIGIBILITY-ELG00003 record segment, and some states have overlooked this. If the ENROLLMENT-TYPE changes, then the state should update the CHIP-CODE valid value to align to the new enrollment.

1 Appendix F: The Eligibility Group Table lists all Medicaid and CHIP eligibility groups under a series of headers to help states classify an individual into these programs.

T-MSIS File Type
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