Why is the variable for date missing for the majority of respondents?

We were checking the data and seemingly 82% of the respondents do not have a value for the date of their survey. We need this for our research. The remaining sample may be large enough but we need to know if the date missing is due to an endogenous factor. It does not seem to be related to interview type.

It appears that you are seeing a large number of missing dates because you have included “ATUS respondents, ATUS nonrespondents, and members of their households” as part of your sample. Time use data are only available for ATUS respondents.

You can analyze records with non-missing date values in two ways: (1) you can select only “ATUS respondents” for your sample when creating your extract or (2) you can use the variable LINENO to identify ATUS respondents. ATUS respondents always have a LINENO value of 1.