Introduction to grandparent pointer variables

The October 2006 release of NAPP data contains six new variables that describe the location in the household of co-resident grandparents. These variables are analogous to the existing spousal (SPLOC) and parental (MOMLOC, POPLOC) location variables in NAPP and IPUMS, described further here. The pointer variables contain the person number within the household of the individual's spouse or parent if they live in the same household, and 0 otherwise.

The grandparent pointers (GRANDMOM, GRANDPOP, MOMMOM, MOMPOP, POPMOM, POPPOP) are analogous. The value of the variable points to the person in the household who is the individual's grandparent. However, because of ambiguities about identifying which side of the family a grandparent might belong to we have created six grandparent variables.

Maternal grandparents (MOMMOM and MOMPOP) are identified by mapping a person's mother's MOMLOC and POPLOC onto the person's MOMMOM and MOMPOP variables.

Maternal grandparents (POPMOM and POPPOP) are similarly identified by mapping a person's father's MOMLOC and POPLOC onto the person's POPMOM and POPPOP variables.

Grandparents identified in the preceding four variables are living in households where parts of three generations of a family are present.

Grandparents who cannot be linked to grandchildren via the intervening generation are identified in GRANDMOM and GRANDPOP. The same individual who is a grandparent is never identified in both GRANDMOM and either of MOMMOM or MOMPOP. Most individuals linked via GRANDMOM or GRANDPOP are living in households where the intervening generation is not present. The household arrangements are typically one of the following:

1. The grandparent (or their spouse) is the head of the household, and at least one grandchild is present in the house, or
2. A grandchild is head of the household, and their grandparents are also resident. Siblings of the head are also linked to the same grandparents

Our principle in constructing these variables was to avoid identifying people as maternal or paternal grandparents when we were not sure. You may use surname information to infer which side of a family grandparents not linked to an intervening parent are from.

It may be noted that while it is theoretically quite possible that grandchildren might be living with three or four of their grandparents, with no intervening generation of parents, thereby overloading our solitary GRANDMOM and GRANDPOP variables, we did not observe this occurring in any of the datasets, containing a total of 90 million people. However, if users spot a case like this we would welcome feedback.

The grandparent pointers may be used to construct variables describing characteristics of own grandparents or own grandchildren, in a way similar to that suggested for parental and spousal characteristics.