Comparing Place of enumeration with Place of usual residence

The Census is collected on a place of enumeration basis. This means that wherever you are staying on Census Night is where you fill in a form and are counted.

One of the questions we ask on the Census form is “Where does the person usually live?”

Answers can be the same as the current location (place of enumeration) or at a different address. This creates two sets of data. The place of enumeration dataset is a count of where people were on Census Night. The place of usual residence dataset records where people usually live.

Place of enumeration is where a person is counted on Census Night. It is considered neither a person, family, nor dwelling level variable but rather a geography and can be applied to all levels of data. For more information, see Australian Statistical Geography Standard (ASGS) Edition 3. 

Most people are enumerated at home on Census Night. The table below shows the proportion of people who were counted at home for the past four censuses.

Census counts based on place of enumeration can be provided for individual Mesh Blocks (MBs) and any aggregations of Mesh Blocks, such as postal areas or Statistical Areas Level 2 (SA2s) or above. This means that a place of enumeration dataset can be as small as a single suburb or as large as Australia.

Place of enumeration data provides a good representation of any given day because there will always be people visiting, occupying non-private dwellings, or travelling that are not obvious when place of usual residence data is used.

Place of usual residence (PURP) refers to where a person usually lives regardless of where they were on Census Night. It is not considered a geography; rather it is a person level variable and can only be applied to people, not families or dwellings.

We use the responses to questions on place of usual residence to code people to a Mesh Block of usual residence. The place of usual residence (PURP) variable is hierarchical which means that Census counts based on PURP can be also be aggregated to higher levels of geography. When using place of usual residence data people are not coded to a specific dwelling or family but are instead linked back to the area they usually live.

This data is less likely to be impacted by seasonal influences because it only includes the usual residents of a particular area, not visitors. This is useful for data users who want to know about the local population. For example, you can use the age structure of the people who live in an area to work out how to distribute funds for health services.

In the table below you can see the total populations for four areas in Western Australia at the SA3 geography level.

The place of enumeration column contains the total number of persons present in each SA3 on Census Night, including overseas visitors and guests.

The place of usual residence column contains the total number of residents that usually live in dwellings located in these areas.

As seen in the tables, some areas contain an increased total population when looking at place of enumeration. Areas such as East Pilbara and West Pilbara have larger enumerated populations when compared with their usual residence totals, most likely due to an influx of fly-in fly-out workers in the mining industry.

This is not always the case. Places such as Cottesloe-Claremont might have their populations remain static on Census Night, with little or no increase in their total populations. In some cases, the enumerated population might even be smaller, such as in Rockingham.

One reason why we usually have a Census on an August date is to minimise the impact of travel, by avoiding major public holidays and school holidays. When large numbers of people are away from where they usually live, it increases the difficulty of data collection.

Firstly, a dwelling does not move. It does not have a place of usual residence. Also, all the variables associated with a dwelling belong to that dwelling and cannot be moved. It is not logical to count the number of bedrooms in a dwelling by place of usual residence. The number of bedrooms belongs to a particular dwelling and they do not move, regardless of whether the people within them do.

Secondly, using place of usual residence will produce a number that is misleading and likely to be incorrectly interpreted.

For example: Using the illustration below, imagine there are five dwellings with male and female residents represented as outline figures. Now count the number of dwellings by sex.

This would produce a table showing the count of dwellings containing females as four and the count of dwellings containing males as four, suggesting a total of eight dwellings. However, there are only five dwellings.

A similar miscount would occur if families were being counted by sex instead of dwellings.

The 2021 Census was conducted during the COVID-19 pandemic, which required much of the Australian population to isolate at home under health directives. This may have caused some differences in counts of Place of enumeration and Place of usual residence in the 2021 Census compared with previous censuses. A slightly higher proportion of the Australian population reported being at home on Census Night than in the previous Census.

Also, there may be some people more strongly affected by lockdown and quarantine laws than others. For example, counts of transitory populations such as agricultural employees, tourists, and international students may be different in some regions compared to Census data in previous years.