Constructed Family Interrelationship variables
NAPP-Constructed Family Interrelationship Variables
NAPP contains a consistent, versatile, and reliable set of constructed variables that describe a variety of family interrelationships among individuals within the same household. Researchers can use them to easily link characteristics of one family member to another - spouses to spouses, children to either or both of their parents, and so on - thereby speeding up analyses of family structures and characteristics. These variables are based on the same programs used for the IPUMS family interrelationship variables.
Basic Family Interrelationship Variables: SPLOC, MOMLOC, and POPLOC
Each of the censuses—except the 1871 and 1881 Canadian and the 1819 Mecklenburg-Schwerin censuses—contains a variable indicating the relationship of each household member to the head of household. In most cases this variable reports relationship as it was listed on the census form, but the 1850-1870 censuses contained imputed household relationships. The general codes for the NAPP version of this variable, called RELATE (Relationship to household head/householder), are fully compatible across all countries. While RELATE provides basic family relationship information, it cannot identify all family relationships and is therefore often inconvenient as a tool for constructing new family variables.
Consider the household in Table 1. RELATE sufficiently establishes that the two daughters are both children of the household head/householder, but to identify the other family interrelationships we must look to the daughters' other characteristics. We can infer that the son-in-law is married to the second daughter rather than the first one because they share the same surname and are both listed as married. For analogous reasons, we know that the grandchild is probably the child of the second daughter listed. It is also safe to assume that the two boarders are married to one another because they are both married, they share the same surname, they are both adults close to the same age, and they are listed adjacently.
Table 1. Family Relationships to Household Head
| Surname | Relationship | Age |
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| Gaffield | Head | 61 |
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| Gaffield | Daughter | 32 |
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| Thorvaldsen | Son-in-law | 32 |
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| Thorvaldsen | Daughter | 27 |
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| Thorvaldsen | Grandchild | 4 |
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| Woollard | Boarder | 26 |
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| Woollard | Boarder | 22 |
To allow users to identify relationships among spouses, parents, and children without forcing them to use multiple variables and complicated logic, NAPP includes a set of pointers called SPLOC, MOMLOC, and POPLOC. These pointers identify the location within the household of each individual's own spouse, mother, and father, respectively. Table 2 illustrates these variables. PERNUM (Person number in unit) is a NAPP variable that indicates each individual's position within the household as listed on the original census form. SPLOC shows the PERNUM of each individual's own spouse. In Table 2, the son-in-law is married to the second daughter, and her PERNUM is 04. Therefore, the son-in-law's SPLOC is 04-the same as his wife's PERNUM. MOMLOC and POPLOC show the PERNUMs of own mothers and own fathers; for example, the mother and father of the grandchild are in positions 04 (MOMLOC) and 03 (POPLOC). Of course, many persons do not have a spouse, mother, or father living in the household with them; these cases are assigned a code of 00 for the appropriate variable(s).
Table 2. Family Relationships with SPLOC, MOMLOC, and POPLOC
| Surname | Relationship | ||||
| Gaffield | Head | ||||
| Gaffield | Daughter | ||||
| Thorvaldsen | Son-in-law | ||||
| Thorvaldsen | Daughter | ||||
| Thorvaldsen | Grandchild | ||||
| Woollard | Boarder | ||||
| Woollard | Boarder |
SPLOC, MOMLOC, and POPLOC can be used to identify conjugal units, to attach characteristics of spouses or parents, to develop specialized own-child measures, or to serve as building blocks for more elaborate measures of family composition. Spouse and parent characteristics can be attached during the data extraction process. In most cases, users will be able to manipulate these variables to construct their own measures within a statistical package and will not be forced to resort to higher-level programming.
Most scholarly family classification schemes are built up from information on the presence of immediate kin. The basic Census Bureau classifications focus on the presence of spouses and children of the household head/householder; the Laslett scheme widely used by historians is based on a count of "conjugal family units" consisting of parents and children or married couples. SPLOC, MOMLOC, and POPLOC make it relatively simple to construct such classifications.
Family historians are increasingly moving from household-level schemes of family classification toward individual-level measures of family structure. For example, instead of measuring the proportion of households headed by a single female parent, we might assess the proportion of women who were single parents or the proportion of children residing with mothers only. Such individual-level analyses offer a variety of advantages that have been detailed elsewhere. The individual-level NAPP pointer variables are especially suited for creating these kinds of measures.
Additional Constructed Family Variables
In addition to SPLOC, MOMLOC, and POPLOC, NAPP provides a variety of other constructed variables to aid researchers in creating new family variables. Four of the constructed variables apply to entire households. NFAMS counts the number of families present in the household. For this purpose a family is defined as any group of persons with identifiable relationships by blood, marriage, or adoption. A single individual residing without any relatives is considered a separate family. Thus, a household consisting of an elderly widow residing with a servant would count as two families, and a large extended family with multiple generations but no boarders, lodgers, or servants would count as a single family. NCOUPLES (Number of married couples), NMOTHERS (Number of mothers), and NFATHERS (Number of fathers) are based on counts of non-zero values in SPLOC, MOMLOC, and POPLOC, respectively.
The United States 1850-1870 censuses did not record relationship to head of household or marital status - the two most important variables for identifying parental and spousal relationships. However, the 1850-1870 censuses contained sufficient information to reliably impute most family relationships. The resulting variables are comparable to the key family relationship and interrelationship variables for other years, allowing researchers to incorporate U.S. 1850-1870 into analyses of change over time. For ease of analysis, the IPUMS imputed family relationships are included with the NAPP relationship and family interrelationship variables.
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