Up to Wave R (except for Wave O), HGSIZE was collected only in the first interview with new households. In case a household had moved or whether a household‘s housing unit size had changed due to renovations or additions (up to Wave G, these households filled out a “green” questionnaire). From Wave S onwards, the question on the size of the housing unit has been posed to all households annually. For households still residing at their old address and neither having moved nor renovated their dwelling, the information on the size of the housing unit is carried forward as a status variable in order to provide valid current information. Analogously, the information is carried back to fill gaps if households missed to state the size of the housing in the first year after moving.

In the case the information on the size of the housing unit is still missing, it is imputed simultaneously with other variables using Stata‘s chained imputation procedure. Imputed values are not carried forward. For information on the imputation procedure, see the description of HGRENT.