In the National Crime Victimization Survey -- which is fielded by the Census Bureau -- the "Reference Person" replaces what was once referred to as the "head of the household." There is also a "Principal Person" which is the person who completes the portion of the survey pertaining to the household. In practice, in a married female-male couple, the male partner is considered the "reference person" while the female partner is the "principal person."
From p. 593 of the 2016 NCVS codebook available on ICPSR: "REFERENCE PERSON: The person identified by the household respondent as owning, buying, or renting the living quarters. This person will generally be at least 18 years of age or older; however, if no one in the household is 18 years of age, the interviewer will choose the person who is identified as owning or renting the living quarters. The reference person replaces the former concept of "head of household" and is not necessarily the same as the household respondent or principal person."
From p. 590 of the 2016 NCVS codebook available on ICPSR: "PRINCIPAL PERSON: In husband/wife living arrangements, this person is the wife. In non-husband/wife living arrangements, this person is the reference person. The principal person's demographic characteristics are used in forming the household weight."
From p. 573 of the 2016 NCVS codebook available on ICPSR: "HEAD OF HOUSEHOLD: Prior to 1979, one person in each household was designated as "head," usually the person reported by the members of the household to be the head. Beginning in 1979 a non-head of household approach was instituted and interviewers were instead instructed to designate a "reference person" -- the household member who owns, is buying, or is renting the housing unit. The reference person may be any one household member 18 years of age or older -- usually the first person listed in the household membership. If all household members are under 18, the interviewer will choose the person identified as owning or renting the living quarters."
doi.org/.../ICPSR36828.v4