PARTNERPNUM is available starting in 2006. IHIS offers a constructed variable SPLOC that reports the person number (PERNUM) of every person's spouse or cohabiting partner from 1963 forward. PARTNERPNUM and SPLOC overwhelmingly agree for years when PARTNERPNUM is available.

Users should note that SPLOC is constructed by IHIS and is based on the IHIS-constructed person number PERNUM. Researchers should use PERNUM with YEAR, SERIAL, and FAMNUMR to uniquely identify household members.

PARTNERPNUM is constructed by the NHIS and must be used with the corresponding person number PX. Researchers should use PX with YEAR, HHX, and FMX to uniquely identify household members.