Description

POP2RULE is a constructed variable that indicates the method by which the probable child-father link shown in POPLOC2 was identified. POPLOC2 is only non-zero when the parents identified for a person are both men. The person identified in POPLOC2 will be the spouse or partner (SPLOC) of the person identified with POPLOC.

In 2017, the family interrelationship variables for samples from 1970 to present were revised to increase comparability across IPUMS projects and include same-sex couples. Many researchers who are familiar with the previous version of family interrelationship variables will find it useful to read a brief overview of the key differences of the New IPUMS Family Interrelationship Variables. On this page you'll find information on how family interrelationship variables are constructed, common uses of these variables, and specific examples of how these variables can be used efficiently.

Samples prior to 1970 do not link same-sex couples or same-sex parents, so POP2RULE does not exist prior to 1970.

The IPUMS family interrelationship variables (1970 samples to present) address two types of ambiguity when forming links. First, we prioritize links based on how clear the relationship is between the two people being linked. Second, when links are not unique we use a series of logical steps to select between multiple potential parents. MOMRULE, POPRULE, MOM2RULE, and POP2RULE are all two digit variables that show how these two types of ambiguity were addressed when forming a parental link. The first digit indicates how direct the relationship is between the two people and the second digit indicates if the link was selected among multiple options and, if so, how it was selected.

We first prioritize links within a household based how clear the relationship is between the two people being linked (using RELATE). The links in the first priority level are direct links, so there are no age restrictions placed on these links. For links in the second priority level, the difference in the age of the "child" half of the link the "parent" half of the link must be 15 to 44 for mothers and 15 to 60 for fathers. For links in the third through fifth level, the same age difference restrictions apply. In addition, third- through fifth-level links only occur when the "child" half of the link is under 22 and is single.

The RELATE values below depend on the in-law editing process described here.

Direct links:
Parental rule value: 1-

• Child to Householder

• Householder to Parent

• Sibling to Parent

• Spouse to Parent-in-law

2nd level links
Parental rule value: 2-

• Grandchild to Child

• Cousin to Aunt/Uncle

• Parent to Grandparent

• Sibling-in-law to Parent-in-law

• Child to Spouse, Partner

3rd level links
Parental rule value: 3-

• Grandchild to Child-in-law

• Other relative to Other Relative, Niece/Nephew, Sibling , Sibling-in-law

• Employee to Employee

• Partner/friend to Partner/friend , Employee

• Partner/roommate to Partner/roommate, Employee

• Roomer/Boarder to Roomer/Boarder

• Housemate to Housemate

• Roomer to Roomer

• Nonrelative to Partner, Nonrelative, Partner/roommate

The allowed relationship links for determining a person's probable parent vary over time because of the level of detail collected regarding the relationship to the reference person. For example, "Grandparent" is an option for RELATE in 1980, 1990, and 2000 but not other years. This means a link between a "Parent" and a "Grandparent" can only happen in those years.

While the first step to finding a spouse or parental link is based on their relationship to the reference person, this may not enough to uniquely determine the link. It is not uncommon for a person to be in a household where there are multiple people who could be their parent. To be able to select among multiple potential links, we apply a set of logical steps within each priority level that selects among multiple potential links. This information is captured in the second digit of POP2RULE.

As shown in the list below, parental links that are direct are made first, because these links are unique. For example, a person identified as the child of the householder will link directly to the householder. For those who were not linked to a parent through a direct link, the second step identifies people in households where there is one married couple who could be their parents. If there are multiple people who could pair to multiple married parents, they are split by age; for example, the eldest children will pair with the eldest couple. If there are no married couples that are possible parents, people who were previously married are selected as parents. If there are no parents who were previously married, the eldest single woman will be identified as the parent. The last potential parent who will be identified is a single man.

Clarity level 1
Parental rule value: -1

• This step identifies parents through links that are uniquely identified by relationship (direct links from previous list).

Clarity level 2
Parental rule value: -2

• When a person is in a household where there is one married couple who could be his/her parents. This couple is identified as the probable parents.

Clarity level 3
Parental rule value: -3

• When a person is in a household where there are multiple married couples who could be his/her parents. Age is used to create pairings.

Clarity level 4
Parental rule value: -4

• When a person is in a household with no married couple who could be their parent, but there is only one potential unmarried parent in the household. This person is identified as their parent.

Clarity level 5
Parental rule value: -5

• When a person is in a household with no married couple who could be their parent and there are multiple possible parents. The first option selected is a woman who was previously married.

Clarity level 6
Parental rule value: -6

•  When a person is in a household with no married couple who could be their parent, there is no previously married woman who would be their parent, and there are multiple possible parents. This step will identify a man who was previously married as the parent.

Clarity level 7
Parental rule value: -7

• When a person is in a household with no married couple or previously married people who could be their parent. In this step, the eldest single woman is selected as the parent.

Clarity level 8
Parental rule value: -8

• When a person is in a household with no married couple, previously married people, or single women who could be their parent. In this step, the eldest single man is selected as the parent.

The two steps together determine the value of POP2RULE. For example, in a household consisting of a male householder, a male unmarried partner, and a child, the householder will be identified as the child's first father with POPLOC and the partner will be identified with POPLOC2. Both links happens with priority 1 during clarity level 1. POPRULE and POP2RULE would therefore be 11.

00 = No second father of this person in the household.

Comparability

Due to variation in the information available for linking mothers and children, there are some differences across years. For example, "Grandparent" is an option for RELATE in 1980, 1990, and 2000 but not other years. This means a link between a "Parent" and a "Grandparent" can only happen in those years.

Comparability with other IPUMS Projects
The development of new family interrelationship variables was prompted by the desire to have more comparability between different IPUMS projects and over time. Each project has different allowed links because of different level of detail in each project, but the logic of assigning parents in ambiguous situations is the same.

Universe

Availability

• 2023: All samples
• 2022: All samples
• 2021: All samples
• 2020: All samples
• 2019: All samples
• 2018: All samples
• 2017: All samples
• 2016: All samples
• 2015: All samples
• 2014: All samples
• 2013: All samples
• 2012: All samples
• 2011: All samples
• 2010: ACS; ACS 3yr; ACS 5yr
• 2009: All samples
• 2008: All samples
• 2007: All samples
• 2006: All samples
• 2005: All samples
• 2004: All samples
• 2003: All samples
• 2002: All samples
• 2001: All samples
• 2000: All samples
• 1990: All samples
• 1980: All samples
• 1970: All samples
• 1960: --
• 1950: --
• 1940: --
• 1930: --
• 1920: --
• 1910: --
• 1900: --
• 1880: --
• 1870: --
• 1860: --
• 1850: --

• 2023: All samples
• 2022: All samples
• 2021: All samples
• 2020: All samples
• 2019: All samples
• 2018: All samples
• 2017: All samples
• 2016: All samples
• 2015: All samples
• 2014: All samples
• 2013: All samples
• 2012: All samples
• 2011: All samples
• 2010: PRCS; PRCS 3yr; PRCS 5yr
• 2009: All samples
• 2008: All samples
• 2007: All samples
• 2006: All samples
• 2005: All samples
• 2000: All samples
• 1990: All samples
• 1980: All samples
• 1970: All samples
• 1930: --
• 1920: --
• 1910: --

Flags

This variable has no flags.

Editing Procedure

There is no editing procedure available for this variable.