Skip to main content
U.S. flag

An official website of the United States government

Return to Search

CMS Guidance: Reporting Eligible Identifiers in T-MSIS

Final

Issued by: Centers for Medicare & Medicaid Services (CMS)

Issue Date: September 25, 2020

CMS Guidance: Reporting Eligible Identifiers in T-MSIS

Guidance History

Date Description of Change
6/3/2020 Original guidance issued
9/25/2020 Language added to clarify the ELG-IDENTIFIERS-ELG00022 Segment Example1 - Reporting Medicaid Card ID of a Medicaid and CHIP beneficiary to T-MSIS

Background and Brief Issue Description

The data captured in T-MSIS is valuable for researchers who are building and evaluating innovation models. It provides researchers with historical data on model participants, as well as control data to compare against. As researchers began to use the T-MSIS data, several shortcomings were noted. It can be difficult to link data collected independently of T-MSIS with data residing in T-MSIS for many states. A major factor causing this challenge is that some states do not use a Medicaid beneficiary’s Medicaid Card ID as their MSIS-IDENTIFICATION-NUM in T-MSIS. Beneficiary identifiers in T-MSIS (i.e., the MSIS-IDENTIFICATION-NUMs) are also subject to change.

Currently in T-MSIS, states report four types of eligible identifiers: (1) Medicare Health Insurance Claim Numbers (HICNs); (2) Medicare Beneficiary Identifiers (MBIs); (3) Social Security Numbers (SSNs); and (4) MSIS Identification Numbers (MSIS IDs). Some states do not use a beneficiary’s Medicaid Card ID as the MSIS-IDENTIFICATION-NUM on their T-MSIS submissions therefore some researchers need a dedicated field for capturing Medicaid Card ID to be able to track T-MSIS data back to its various sources. CMS is introducing a new record segment (“ELG-IDENTIFIERS-ELG00022”) in the T-MSIS Eligible file to enable linking and managing effectively of the various identifiers associated with a beneficiary over the course of his/her involvement with the Medicaid/CHIP programs.

Some uses for this new segment are:

  • States will use this segment to report each Medicaid and CHIP beneficiary’s Medicaid Card ID and the active time period for the corresponding identifiers.
  • States will also use this segment to report changes in a beneficiary’s MSIS Identification Number due to disenrollment/re-enrollment, record merges, large system enhancements, and transition from CHIP enrollment to Medicaid enrollment or from Medicaid enrollment to CHIP enrollment.
By capturing additional information and potential identifier changes over time, the new segment will allow CMS and researchers to better link identifiers and merge the beneficiary into one entity. The guidance in this brief defines the layout of the ELG-IDENTIFIERS-ELG00022 segment and each type of eligible identifier captured in T-MSIS and provides a high-level description of how states’ source systems can validate eligible identifier values for reporting in T-MSIS.

Eligible File New Segment – ELG-IDENTIFIERS-ELG00022

The new record segment, ELG-IDENTIFIERS (ELG00022), captures the identifiers assigned to a beneficiary by various entities.

This segment is critical for linking across data sources over time. The new ELG-IDENTIFIER-TYPE (ELG261) data element is used to identify whether the segment is reporting a beneficiary’s state-assigned Medicaid Card ID, Old MSIS Identification Number. The state should provide the appropriate ELG-IDENTIFIER-TYPE code and supply the associated ID in the ELG-IDENTIFIER data element. Table 1 below shows the layout for the ELG-IDENTIFIERS-ELG00022 segment.

Table 1: Record Segment Layout for ELG-IDENTIFIERS-ELG00022
DE_NO DATA_ELEMENT_NAME SIZE START POSITION STOP POSITION STOP POSITION
ELG257 RECORD-ID X(8) 1 8 An identifier assigned to each record segment. The first 3 characters identify the subject area. The last 5 bytes are an integer with leading zeros. For example, the RECORD-ID for the PRIMARY DEMOGRAPHICS – ELIGIBILITY record segment is ELG00002.
ELG258 SUBMITTING-STATE X(2) 9 10 The ANSI numeric state code for the U.S. state, territory, or the District of Columbia that has submitted the data.
ELG259 RECORD-NUMBER 9(11) 11 21 A sequential number assigned by the submitter to identify each record segment row in the submission file. The RECORD-NUMBER, in conjunction with the RECORD-ID, uniquely identifies a single record within the submission file.
ELG260 MSIS-IDENTIFICATION-NUM X(20) 22 41 A state-assigned unique identification number used to identify a Medicaid/CHIP enrolled individual and any claims submitted to the system.
ELG261 ELG-IDENTIFIER-TYPE X(1) 42 42 A code to identify the kind of eligible identifier that is captured in the ELG-IDENTIFIER data element.
ELG262 ELG-IDENTIFIER-ISSUING-ENTITY-ID X(18) 43 60 This data element is reserved for future use.
ELG263 ELG-IDENTIFIER-EFF-DATE 9(8) 61 68 The first day of the time span during which the values in the ELG-IDENTIFIERS-ELG00022 record segment are in effect (i.e., the values accurately reflect reality as it is understood to be at the time the record is created). This date field is necessary when defining a unique row in a database table.
ELG264 ELG-IDENTIFIER-END-DATE 9(8) 69 76 The last day of the time span during which the values in the ELG-IDENTIFIERS-ELG00022 record segment are in effect (i.e., the values accurately reflect reality as it is understood to be at the time the record is created).
ELG265 ELG-IDENTIFIER X(20) 77 96 A data element to capture the various identifiers assigned to Medicaid and CHIP beneficiary by various entities. The specific type of identifier is shown in the corresponding value in the ELG-IDENTIFIER-TYPE data element.
ELG266 REASON-FOR-CHANGE X(10) 97 106 A code to identify the reason for changing the MSIS- IDENTIFICATION-NUM of a beneficiary and only required for ELG-IDENTIFIER-TYPE '2-Old MSIS Identification Number'. For example, If MSIS- IDENTIFICATION-NUM of a beneficiary is being changed due to 'Merge with other MSIS ID' or 'Unmerge'.
ELG267 STATE-NOTATION X(500) 107 606 A free text field for the submitting state to enter whatever information it chooses.
ELG268 FILLER X(394) 607 1000

Record Segments Keys

The following data elements are the record segment keys of ELG-IDENTIFIERS-ELG00022 segment

  1. SUBMITTING-STATE
  2. MSIS-IDENTIFICATION_NUM
  3. ELG-IDENTIFIER-TYPE
  4. ELG-IDENTIFIER
  5. ELG-IDENTIFIER-EFF-DATE

As shown in Figure 1, the ELG-IDENTIFIERS-ELG00022 segment is a child to the PRIMARY-DEMOGRAPHICS-ELIGIBILITY-ELG00002 segment and links to that segment by the required data elements SUBMITTING-STATE, MSIS-IDENTIFICATION-NUM. Each record in the ELG-IDENTIFIERS-ELG00022 segment must have corresponding records in the PRIMARY-DEMOGRAPHICS-ELIGIBILITY-ELG00002 segments that contain effective and end-date ranges that span the effective and end-date range reported in the ELG-IDENTIFIERS-ELG00022 segment.

Figure 1. Table Relationship for ELG-IDENTIFIERS-ELG00022

Definitions for the Data Elements in the ELG-IDENTIFIERS-ELG00022 Segment

Critical fields that can be used to assess the validity of the ELG-IDENTIFIERS-ELG00022 segment information include ELG-IDENTIFIER-EFF-DATE (ELG263), ELG-IDENTIFIER-END-DATE (ELG264), ELG-IDENTIFIER-TYPE (ELG261), ELG-IDENTIFIER (ELG265) and REASON-FOR-CHANGE(ELG266). This section reviews these fields.

ELG-IDENTIFIER-EFF-DATE and ELG-IDENTIFIER-END-DATE

ELG-IDENTIFIER-EFF-DATE is a required field and represents the first day of the time span during which the values in all data elements in the ELG-IDENTIFIERS-ELG00022 segment are in effect. ELG-IDENTIFIER-EFF-DATE must be a valid date and populated in CCYYMMDD format.

ELG-IDENTIFIER-END-DATE represents the last day of the time span during which the values of the data elements in the ELG-IDENTIFIERS-ELG00022 segment are in effect.

ELG-IDENTIFIER-TYPE

ELG-IDENTIFIER-TYPE is a code that identifies the kind of identifier captured in the ELG-IDENTIFIER data element. For every unique combination of SUBMITTING-STATE and MSIS-IDENTIFICATION-NUM, states should provide to T-MSIS the identifiers associated with the beneficiary for ELG-IDENTIFIER-TYPE 1 always and ELG-IDENTIFIER-TYPE 2 whenever it is applicable to the beneficiary. If a beneficiary has multiple identifiers for the same ELG-IDENTIFIER-TYPE, then a separate record segment should be reported for each identifier. For example, if a beneficiary has two old MSIS Identification Numbers, then a separate record segment for each of the old MSIS Identification Numbers should be reported with an ELG-IDENTIFIER-TYPE of “2” and their respective effective and end dates. Table 2 below shows the valid values and associated descriptions.

Table 2: ELG-IDENTIFIER-TYPE Values
Code Identifier Description
1 Medicaid Card ID The Medicaid Card ID is a state-assigned unique identifier that states should report with all Medicaid and CHIP beneficiaries. This should be the identifier that is used in the state’s Medicaid Management Information System (MMIS). The beneficiary’s Medicaid Card ID should be reported even if the Medicaid Card ID is the same as the Medicaid Identification Number used in T-MSIS.
2 Old MSIS Identification Number The Old MSIS Identification Number identifier type is a value that states should report for all Medicaid and CHIP beneficiaries when their MSIS Identification Number is changed due to record merges, unmerges, large system enhancements, and transition between CHIP and Medicaid enrollment.

REASON-FOR-CHANGE

REASON-FOR-CHANGE is a code that identifies the reason for changing the MSIS-IDENTIFICATION-NUM of a beneficiary. This is applicable for ELG-IDENTIFIER-TYPE = 2, (Old MSIS Identification Number). For example, MSIS-IDENTIFICATION-NUM of a beneficiary is being changed due to 'Merge with other MSIS ID' or 'Unmerge'. Table 3 below shows the valid values and associated descriptions.

Table 3: REASON-FOR-CHANGE Values
Code Description
MERGE Merge Beneficiaries - if the state was reporting multiple Medicaid Identification Numbers for a single beneficiary and merges them under a single MSIS Identification Number.
UNMERGE Unmerge Beneficiaries - if the state unmerges a beneficiary from another beneficiary. For example, if a newborn child is originally reported with the mother’s MSIS Identification Number and is then assigned a different MSIS Identification Number.
LSE Large System Enhancement - if the state assigns a new MSIS Identification Number to any beneficiaries during large system enhancement in state MMIS.
TCAM Transition between CHIP and Medicaid - if the Medicaid and Separate CHIP programs use different Identifier Number schemas and beneficiaries are transferred from CHIP to Medicaid or from Medicaid to CHIP and a new MSIS Identification Number is issued.

CMS Guidance

States should work with their eligibility determination system to ensure that they implement the following best practices when assigning identifiers to beneficiaries during enrollment.

  1. The ELG-IDENTIFIERS-ELG00022 data segment is being populated correctly.
  2. Using the external resources that are available, the state should validate beneficiary’s identifiers during the enrollment process. Table 2 above shows available data sources by ELG-IDENTIFIER-TYPE. When preparing T-MSIS files, states should determine whether the identifiers comply with the stated validation criteria. If they do not, states should coordinate with the MMIS vendor to ensure that the data are being properly captured in the source systems.

  3. States should adhere to the ELG-IDENTIFIERS-ELG00022 coding requirements as stated below and in Table 4.

Coding Requirements

Table 4: Coding Guidance
SEGMENT /DE_NO DATA_ELEMENT_NAME CODING REQUIREMENTS
ELG-IDENTIFIERS-SEG00022 N/A Required data elements on the ELG-IDENTIFIERS-ELG00022 segment—SUBMITTING-STATE, MSIS-IDENTFICATION-NUM, ELG-IDENTIFIER, ELG-IDENTIFIER-TYPE, ELG-IDENTIFIER-EFF-DATE, and ELG-IDENTIFIER-END-DATE. These data elements are necessary for the ELG-IDENTIFIERS-ELG00022 segment to be meaningful and useful.
ELG-IDENTIFIERS-SEG00022 N/A

Table 2. above Validating Eligible Identifiers - ELG-IDENTIFIER-TYPE Validation procedures to conform with MMIS. ELG-IDENTIFIER-TYPE should be properly formatted.

  • 1-Medicaid Card ID (State MMIS)
  • 2-Old MSIS Identification Number (State MMIS)
ELG-IDENTIFIERS-SEG00022 N/A

For every ELG-IDENTIFIERS-ELG00022 record segment,

  1. There must be an active corresponding PRIMARY-DEMOGRAPHICS-ELIGIBILITY-ELG00002 record segment.
  2. Both ELG-IDENTIFIER-EFF-DATE and ELG-IDENTIFIER-END-DATE must be valid dates and fall within a corresponding time span for the same SUBMITTING-STATE, MSIS-IDENTIFICATION-NUM combination in the PRIMARY-DEMOGRAPHICS-ELIGIBILITY-ELG00002 segment.
ELG-IDENTIFIERS-SEG00022 N/A

For every ELG-IDENTIFIERS-ELG00022 record segment, the state should provide the identifiers for ELG-IDENTIFIER-TYPE 1 and 2. Reporting ELG-IDENTIFIER-TYPE 1 is always required and ELG-IDENTIFIER-TYPE 2 is conditionally required.

  1. States should always provide at least one Medicaid Card ID with ELG-IDENTIFIER-TYPE=1 to T-MSIS for every Medicaid and CHIP beneficiary.
  2. States should provide all Old MSIS Identification Number with ELG-IDENTIFIER-TYPE=2 to T-MSIS in case the state changes the MSIS-IDENTIFICATION-NUM of a beneficiary.
ELG257 RECORD-ID
  1. Value must be equal to a valid value.
  2. Must be populated on every record segment.
ELG258 SUBMITTING-STATE
  1. Value must be equal to a valid value.
  2. Must be populated on every record.
  3. Value must be numeric.
  4. Value must be the same on all record segments.
ELG259 RECORD-NUMBER
  1. Value must be an 11-digit integer with no commas.
  2. Value must be numeric.
  3. RECORD-ID/RECORD-NUMBER combinations should be unique within a state's submission.
ELG260 MSIS-IDENTIFICATION-NUM
  1. MSIS-IDENTIFICATION-NUM must be reported.
  2. A child record segment must have a parent record segment (PRIMARY-DEMOGRAPHICS-ELIGIBILITY-ELG00002).
ELG261 ELG-IDENTIFIER-TYPE
  1. Value must be equal to a valid value.
  2. Required whenever a value is captured in the ELG-IDENTIFIER data element.
  3. The state should provide the identifiers associated with a beneficiary for identifier type 1 always and identifier type 2 whenever it is applicable to a beneficiary.
  4. States should always provide at least one Medicaid Card ID with ELG-IDENTIFIER-TYPE=1 to T-MSIS for every Medicaid and CHIP beneficiary.
  5. States should provide all Old MSIS Identification Number with ELG-IDENTIFIER-TYPE=2 to T-MSIS in case the state changes the MSIS-IDENTIFICATION-NUM of a beneficiary.
  6. The state should submit updates to T-MSIS whenever an identifier is retired or issued.
ELG262 ELG-IDENTIFIER-ISSUING-ENTITY-ID This data element is reserved for future use.
ELG263 ELG-IDENTIFIER-EFF-DATE
  1. Date format is CCYYMMDD (National Data Standard).
  2. Value must be a valid date.
  3. Must be populated on every record.
  4. For parent and child file segments, the effective date span of the child record segment must be fully contained within the set of effective date spans of the associated active parent records.
  5. Whenever the value in one or more of the data elements in the ELG-IDENTIFIERS-ELG00022 record segment changes, a new record segment must be created.
  6. The ELG-IDENTIFIER-EFF-DATE must occur on or before the ELG-IDENTIFIER-END-DATE (Unless the segment is a deletion segment. For ‘Delete Segments’ scenario end date would be before effective date).
ELG264 ELG-IDENTIFIER-END-DATE
  1. Date format is CCYYMMDD (National Data Standard).
  2. Value must be a valid date.
  3. Must be populated on every record.
  4. If the time span is open-ended (i.e., there is no end date), then populate the field with “99991231” (end-of-time).
  5. If a complete, valid end date is not available or is unknown, leave blank, or space-fill.
  6. For parent and child record segments, the end date of a child record segment must occur before or be concurrent with the end date of the parent record segment, where submitting state and record segment-specific identifying number match one another in both record segments.
  7. Whenever the value in one or more of the data elements in the ELG-IDENTIFIERS record segment changes, a new record segment must be created.
  8. The ELG-IDENTIFIER-END-DATE must occur on or after the ELG-IDENTIFIER-EFF-DATE
  9. Overlapping coverage not allowed for same Submitting state, MSIS Identification Num, ELG Identifier Type, ELG Identifier
ELG265 ELG-IDENTIFIER
  1. The field can contain any alphanumeric characters, digits or symbols except the "pipe" (|).
  2. The value in the ELG-IDENTIFIER data element should be a valid value in the enumeration entity’s identification schema.
  3. The state should submit updates to T-MSIS whenever an identifier is retired or issued.
  4. The state should provide the identifiers associated with a beneficiary for identifier type 1 always and identifier type 2 whenever it is applicable to a beneficiary.
    Conditions when CMS expects a ELG-IDENTIFIER Value:
    •1- Medicaid Card ID (the state should supply this identifier for every Medicaid and CHIP beneficiary, since it is the state itself that is using the identifier in its MMIS.)
    •2- Old MSIS Identification Number (the state should supply this identifier for beneficiaries in case state change their MSIS Identification Number).
ELG266 REASON-FOR-CHANGE
  1. Value must be equal to a valid value.
  2. The state should submit updates to T-MSIS whenever state changes the MSIS_IDENTIFICATION-NUM of a beneficiary.
  3. Required whenever a value '2' is captured in the ELG-IDENTIFIER-TYPE data element.
  4. State should report ‘REASON-FOR-CHANGE’ when ELG-IDENTIFIER-TYPE is 2 (Old MSIS Identification Number) because the state is changing the MSIS-IDENTIFICATION-NUM of a beneficiary.
    1. States should provide Old MSIS Identification Number with REASON-FOR-CHANGE = ‘MERGE’ to T-MSIS if the state was reporting multiple MSIS Identification Numbers for a single beneficiary and merges them under a single MSIS Identification Number.
    2. States should provide Old MSIS Identification Number with REASON-FOR-CHANGE = ‘UNMERGE’ to T-MSIS if the state unmerges a beneficiary from another beneficiary. For example, if a newborn child is originally reported with the mother’s MSIS Identification Number and is then assigned a different MSIS Identification Number.
    3. States should provide Old MSIS Identification Number with REASON-FOR-CHANGE = ‘LSE‘ to T-MSIS if the state assigns a new MSIS Identification Number to any beneficiaries during large system enhancement in state MMIS.
    4. States should provide Old MSIS Identification Number with REASON-FOR-CHANGE = ‘TCAM’ to T-MSIS if the Medicaid and Separate CHIP programs use different MSIS Identifier Number schemas and beneficiaries are transferred from CHIP to Medicaid or from Medicaid to CHIP and a new MSIS Identification Number is issued.
ELG267 STATE-NOTATION
  1. The field can contain any alphanumeric characters, digits or symbols except the "pipe" (|).
  2. For pipe-delimited files, states can populate the STATE-NOTATION field with “n/a,” “n.a.” or leave the field blank (i.e., submitted as "pipe" with nothing in between (||)) when not using the field to record specific comments.
  3. For fixed-length files, states should space-fill the STATE-NOTATION field when not using the field to record specific comments, and right-pad the field with spaces when the field does contain verbiage.
ELG268 FILLER
  1. For pipe-delimited files, FILLER that is shown at the end of each record layout is applicable only to fixed-length files and therefore should be ignored in pipe-delimited files.
  2. For fixed-length files, FILLER that is shown at the end of each record layout should be space-filled in fixed-length files.

ELG-IDENTIFIERS-ELG00022 Segment Examples

Example1: Reporting Medicaid Card ID of a Medicaid and CHIP beneficiary to T-MSIS

Regardless of whether or not a state uses the same value as both the Medicaid Card ID and the MSIS Identification number, it still must generate an ELG00022 segment that identifies the value as a Medicaid Card ID. Table 5 shows an example where the values for both the Medicaid Card ID and MSIS Identification Number are the same, while Table 6 shows an example where the values are different.

Table 5: ELG-IDENTIFIERS-ELG00022 Example1 State submitting Medicaid Card ID and MSIS-IDENTIFICATION-NUM same
RECORD-ID SUBMITTING-STATE RECORD-NUMBER MSIS-IDENTIFICATION-NUM ELG-IDENTIFIER-TYPE ELG-IDENTIFIER-ISSUING-ENTITY-ID ELG-IDENTIFIER-EFF-DATE ELG-IDENTIFIER-END-DATE ELG-IDENTIFIER REASON-FOR-CHANGE
ELG00022 YY 2001 MCID456 1 (Medicaid Card ID) 01/01/2017 12/31/9999 MCID456
Table 6: ELG-IDENTIFIERS-ELG00022 Example1 State submitting Medicaid Card ID and MSIS-IDENTIFICATION-NUM different
RECORD-ID SUBMITTING-STATE RECORD-NUMBER MSIS-IDENTIFICATION-NUM ELG-IDENTIFIER-TYPE ELG-IDENTIFIER-ISSUING-ENTITY-ID ELG-IDENTIFIER-EFF-DATE ELG-IDENTIFIER-END-DATE ELG-IDENTIFIER REASON-FOR-CHANGE
ELG00022 XX 1001 M001 1 (Medicaid Card ID) 01/01/2019 12/31/9999 MCID123

Example2: Reporting Multiple MSIS IDs of a Medicaid and CHIP beneficiary to T-MSIS when state changes MSIS ID of a beneficiary

A state has reported two beneficiaries with MSIS ID M001 and M003 in the Eligible file. Later, the state identifies that those two beneficiaries are the same person therefore they want to merge the two MSIS IDs into one record. The most recent MSIS ID is M003 and the old MSIS ID is M001. The state should report that information in the new segment as follows:

Table 7: ELG-IDENTIFIERS-ELG00022 Example2
RECORD-ID SUBMITTING-STATE RECORD-NUMBER MSIS-IDENTIFICATION-NUM ELG-IDENTIFIER-TYPE ELG-IDENTIFIER-ISSUING-ENTITY-ID ELG-IDENTIFIER-EFF-DATE ELG-IDENTIFIER-END-DATE ELG-IDENTIFIER REASON-FOR-CHANGE
ELG00022 XX 1001 M001 1 (Medicaid Card ID) 01/01/2019 12/31/9999 MCID123
ELG00022 XX 1002 M003 1 (Medicaid Card ID) 01/01/2019 12/31/9999 MCID123
ELG00022 XX 1003 M003 2-Old MSIS Identification Number 01/01/2019 12/31/9999 M001 MERGE

Example3: Reporting correct MSIS ID of a Medicaid and CHIP beneficiary to T-MSIS when state changes MSIS ID of a beneficiary.

A state has reported a beneficiary with MSIS ID M002 in the Eligible file. Later, the state identifies that they were reporting two beneficiaries’ information under the same MSIS ID (e.g., twin baby information) and then unmerged those two individuals. A new Medicaid Card ID and MSIS ID (M004) is assigned to twin baby B and the existing MSIS ID M002 will be used by twin baby A. The state should report the information in the new segment as follows:

Table 8. Reporting MSIS ID Changes
RECORD-ID SUBMITTING-STATE RECORD-NUMBER MSIS-IDENTIFICATION-NUM ELG-IDENTIFIER-TYPE ELG-IDENTIFIER-ISSUING-ENTITY-ID ELG-IDENTIFIER-EFF-DATE ELG-IDENTIFIER-END-DATE ELG-IDENTIFIER REASON-FOR-CHANGE
ELG00022 XX 1001 M002 1 (Medicaid Card ID) 01/01/2019 12/31/9999 MCID-456
ELG00022 XX 1002 M004 1 (Medicaid Card ID) 01/01/2019 12/31/9999 MCID-789
ELG00022 XX 1003 M004 2-Old MSIS Identification Number 01/01/2019 12/31/9999 M002 UNMERGE

HHS is committed to making its websites and documents accessible to the widest possible audience, including individuals with disabilities. We are in the process of retroactively making some documents accessible. If you need assistance accessing an accessible version of this document, please reach out to the guidance@hhs.gov.

DISCLAIMER: The contents of this database lack the force and effect of law, except as authorized by law (including Medicare Advantage Rate Announcements and Advance Notices) or as specifically incorporated into a contract. The Department may not cite, use, or rely on any guidance that is not posted on the guidance repository, except to establish historical facts.