Comparability
The comparability of this variable is affected by the information available on family relationships. NCHILD is based on the information contained in RELATE (Relationship to household head), MOMLOC, MOMLOC2, POPLOC, and POPLOC2. See MOMLOC, MOMLOC2, POPLOC, and POPLOC2 for discussion of variations across years in these variables.
Comparability with IPUMS-USA
The development of new family interrelationship variables was prompted by the desire to have more comparability between different IPUMS projects and over time. The family interrelationship variables use common logic across different IPUMS projects. 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.
