Description
IMPGT20KFLAG is a variable that indicates whether the value in the variable IMPINCGT20K was directly reported or imputed. The complementary variable IMPINCGT20K was created to provide complete (i.e., without missing values) data on family income; the accompanying flag variables allow researchers to identify in which cases imputation was used.
Beginning in 1997, there are five imputations for each person. However, in 1990-1996 there is only a single imputation for these missing cases. Technical documentation on "Methods Used to Impute Annual Family Income in the National Health Interview Survey, 1990-96" includes information on percentages of missing income data and selection of the imputation method.
