HRS provides a cross-reference file that links the CMS files created by Acumen LLC to HRS. The purpose of this file is to allow Acumen to retrieve the Medicare records of HRS respondents without being able to merge this information to HRS public or restricted files. Steps in this process are:

• HRS provides Acumen with a list of respondents who have given permission for Medicare record analysis. This list is keyed on a sequence number created by HRS
• Acumen replaces the respondent's HIC with a unique identifier (BID) and links that value to the HRS sequence number.
• HRS creates a cross-reference file that links BID to HHIDPN, dropping the sequence number.