New IPUMS family interrelationship variables

IPUMS has made some small modifications to the family interrelationship variables in order to accomplish three important goals.

  1. Increase comparability across different data projects and over time
  2. Adjust to include same-sex couples and other diverse family types
  3. Clearly communicate how the link was identified, so researchers can choose to include or exclude certain links

To accomplish these goals, the new family interrelationship variables have made multiple changes. The first three changes are relatively straightforward. First, SPLOC now links married and cohabiting relationships for same-sex and opposite-sex couples. Second, there are new variables (MOMLOC2 and POPLOC2) that allow parental links to include same-sex couples. Third, there are detailed variables that identify how a spousal or parental link was identified (SPRULE, MOMRULE, POPRULE).

The more complex change affects how IPUMS selects which parental or spousal links to identify when there are multiple potential links to select from. The new IPUMS family interrelationship variables use marital status, age, and sex when deciding among multiple potential parental or spousal links. In contrast to the previous family interrelationship variables, the new variables rarely use household order when deciding links. The logic behind selecting a link is the same across multiple IPUMS datasets, even when there are differences in the level of detail in RELATE.

The spouse location variable first links couples, both same-sex and opposite-sex, where there is only one potential spouse or partner. In households where there are multiple potential spouses, opposite-sex links are prioritized over same-sex links. When there are multiple potential opposite-sex spouses, relative age is used to pair up spouses. When there are two people of the same age, location in the household is used as a "tie breaker". Households that contain multiple same-sex couples are paired as the last logical step, again using relative age to determine who will pair together. The variable SPRULE indicates in which potential link was ultimately chosen for SPLOC.

Below are two example households from different datasets where IPUMS will select a spouse when there are multiple potential spouses. While the two datasets differ in detail of relationship to head, the logic used to assign SPLOC will be the same. In the first household, the 40 year old son of the householder could be married to either daughter-in- law of the householder.

Person number Relationship to head Age Marital status Sex Spouse location
1 Householder 67 Widow F
2 Child 40 Married, spouse present M 4
3 Child 35 Married, spouse present M 5
4 Child-in-law 39 Married, spouse present F 2
5 Child-in-law 34 Married, spouse present F 3

SPLOC will use the relative ages of the potential spouses and indicate that the eldest son is likely married to the eldest daughter-in-law. Likewise, the younger son is likely married to the younger daughter-in-law.

However, another IPUMS dataset may not have "Child-in-law" as a possible value for "Relationship to Head." Many datasets would describe a "Child-in-law" as an "Other relative". This makes the spousal link less clear, because an "Other relative" could be married to many types of people, not just a child of the householder. The following household is very similar to the previous one, but now we have one son, and three other relatives - one male and two female.

Person number Relationship to head Age Marital status Sex Spouse location
1 Householder 67 Widow F
2 Child 40 Married, spouse present M 4
3 Other relative 35 Married, spouse present M 5
4 Other relative 39 Married, spouse present F 2
5 Other relative 34 Married, spouse present F 3

SPLOC will make the same decision as before: The 40 year old son will marry the 39 year old female "Other relative." The 35 year old male "Other relative" will marry the 34 year old female "Other relative."

SPRULE will indicate the logical step was the same in both case, because in both cases age was used to select from multiple potential opposite-sex spouses. However, it will also show that the link in the first dataset was clearer than in the second, because of the finer detail in the relationship to head. For more detailed information, see the SPRULE variable description.

Similarly, when creating parental links, IPUMS uses marital status, age, and sex to decide the most likely parent. For example, married couples will be selected as parents prior to a single person. Single women will be selected before single men. Among multiple single women, the eldest is selected before younger women. If there are multiple children who could pair to multiple married parents, they are split by age. Among single women, all children are assigned to the eldest. These logical steps are the same across multiple IPUMS datasets.

As with SPRULE, MOMRULE and POPRULE will indicate the clarity of the link (e.g, Child to grandchild) as well as how the choice was made if there were multiple potential parents. The specific meanings of MOMRULE's and POPRULE's values for each project are described in more detail in the variable descriptions.

Numerous IPUMS variables depend on the parental location variables, including number of children, number of children less than 5, age of eldest child, age of youngest child, and number of siblings. These variables now use the new IPUMS parental location variables.

A note about attaching characteristics: though the new IPUMS pointers do match self-reported pointers in most cases, there are a few where self-reported and IPUMS pointers differ. The "Attach Characteristics" feature of the IPUMS extract system attaches characteristics from the record identified by the new IPUMS pointers as father, mother, or spouse to a person. For example, if one wishes to attach the father's birth place (BPL value on the record indicated as that individual's father), and if a given household has different records identified as an individual's father by POPLOC (IPUMS) and PELNDAD (self-reported), the "Attach Characteristics" feature will attach the BPL value from the record identified as the father by POPLOC.

Pre-2016 versions of the IPUMS family pointer variables and the other constructed family variables which depend upon these pointers can be found here for IPUMS-CPS.

For more information on the pre-2016 versions of the IPUMS family pointer variables, see the IPUMS Family Interrelationship Variables page.

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