Same-Sex Married Couples and IPUMS-Constructed Family Interrelationship Variables

IPUMS USA has implemented new family interrelationship variables in samples from 1970 to the present that identify same-sex couples. For more information on the new variables, please see the New Family Interrelationships page.

NOTE: Currently, same-sex married couples are only identified by SSMC if the householder (RELATE = 01) is a part of the same-sex married couple. The IPUMS family interrelationship variables now identify these couples as well as cohabiting same-sex couples and married same-sex couples that do not involve the householder. Errors in reported sex can result in an overestimate of the number of same-sex couples.

Identifying Spouses

In samples from 1970 and later, the IPUMS USA spouse pointer variable SPLOC identifies the location (person number) for a person's same-sex spouse or partner.

The ability of IPUMS to identify same-sex spouses and partners depends on the editing procedures used by the data provider. For example, for the years where this is available (2013 and later), SPLOC will link a householder (RELATE = 01) and a same-sex spouse (RELATE = 02). Information on unmarried partners (same-sex or different-sex) is availble in samples from 1990 and later - these couples are also linked by SPLOC.

SPRULE indicates how a SPLOC link was formed both different-sex and same-sex couples.

Identifying "Mothers" and "Fathers"

The parental pointer variables MOMLOC, MOMLOC2, POPLOC, and POPLOC2 identify a child's parents within the household. When the parents are both women, MOMLOC and MOMLOC2 will show the PERNUM values of the parents. If both parents are men, POPLOC and POPLOC2 are used. This applies to all children, whether biological, adopted or step.

The attach characteristics function in the extract system will attach characteristics all identified parents. For example, if you attach the education of the mother the extract system will produce two variables: one containing the education of the person identified with MOMLOC and the second containing the education of the person identified with MOMLOC2.

Number of Children

IPUMS constructs indicators of the number of children linked to an individual by MOMLOC, MOMLOC2, POPLOC, and POPLOC2 (NCHILD and NCHLT5). These variables apply to parents in both same-sex and different-sex couples. They also count both biological and social relationships.

Accuracy of same-sex marriage data in the ACS and Census

Because same-sex marriages are identified using relationship to householder and sex, reporting errors may result in incorrectly identified same-sex marriages. Although errors can occur for all populations, the small size of the same-sex married population relative to the different-sex married population means that the error rate in the reporting of sex has significant implications for the measurement of the same-sex married population.

For more information on the accuracy of same-sex couple data in the ACS please see the Census Bureau Fact Sheet and additional technical documents. The Census Bureau is piloting revised questions that would distinguish between opposite-sex and same-sex relationships.

If researchers more information on the new variables, more information can found on the New Family Interrelationships page.