0 = N.I.U. (Not in Universe; Zero children present).
9 = 9 or more persons (Topcode).
NCHILD counts the number of own children (of any age or marital status) residing with each individual. NCHILD includes step-children and adopted children as well as biological children. Persons with no children present are coded 0.
Note that NCHILD is an IPUMS-derived variable using IPUMS-derived family interrelationships. Thus NCHILD may differ from any family information that comes from the ATUS.
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. These variables are comparable from 2003 onward.
Some RELATE categories are less clear than others, so additional restrictions are placed on creating links in MOMLOC, MOMLOC2, POPLOC, and POPLOC2. For example, the designation as an "Other relative" does not give much information about how this person is related other household members. Likewise, among "Housemates" it is unclear if or how the housemates are related to each other or not. Because these relationships are unclear, IPUMS only creates parental links for "Other relative", "Housemate" "Roomer" and "Non-relatives" when they are single and under 22. As a result, some adult children of another individual in the household may not be included in NCHILD.
Comparability with IPUMS-USA
The development of new family interrelationship variables was prompted by the desire to have more comparability between different IPUMS projects. The family interrelationship variables use common logic across ATUS-X, IPUMS CPS, IHIS, and USA (modern years). 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.
- ATUS respondent household members.