We are using administrative data to help assess which houses were empty on Census night and to help improve the Census count.
We work hard to collect data from every house that was occupied on Census night. We still need to adjust the count for a small number of houses where someone was home, but we haven't received a Census form.
We do this using a process called imputation. Imputation is where we copy basic Census information (number of people with their age and sex) from another similar household to represent the missed people.
We know from looking at results from the 2016 Post Census Review that, despite our best efforts, we sometimes impute data for a house that was actually empty on Census night. If this happens a lot in an area, it can make the counts for that area larger than they should be.
Our research also shows that when we adjust the Census count using imputation, we tend to count more older Australians than we should. You can read more about this on our page Can administrative data help to improve the Census count?