As described in Chapter 4, the Census Bureau often imputes information when a person does not respond to the survey or to a particular question. A variable of interest may be imputed. In the core wave files prior to the 1996 Panel, there is an imputation flag for almost all of the person-level variables. Beginning with the 1996 Panel, there is an allocation flag associated with every variable subject to imputation.
Variables are imputed and the imputation flags are set before composite variables are created.
For example, if income is imputed for one member of a household, that person's imputation flag is set. There is no direct indication on the records of other household members that any information has been imputed. The edit and imputation procedures used for the core wave files are different from the procedures used for the full panel files. The procedures used for the full panel files make use of the full set of longitudinal data for a person. Since the core wave files are processed individually, the edit and imputation procedures applied to those files have at most 4 months of observations for a person.