This page provides general information about the 2011 Census non-response rates for Persons, Items and Dwellings to assist in the use and interpretation of Census data.

Non-response rate tables are available for each state and territory, and the whole of Australia (including Other Territories). These tables are available for Persons by Place of Usual Residence and place of enumeration, and for Dwellings by place of enumeration.

Non-response and the 2011 Census quality statement

Person non-response

Person non-response has fallen from 4.2% of all persons in 2006 to 3.7% in 2011, reversing a trend in earlier Censuses. Person non-response occurs where a Census form is not returned for a private dwelling which is believed to be occupied on Census Night, and where a personal form is not returned for an 'other dwelling' (see note below). Person non-response is a significant component of Census item non-response. The other component is formed where a Census form has been returned for a person but one or more applicable questions have not been answered. A count of non-responding persons is obtained in the Census (either by the Collector or by imputation) and some characteristics are imputed (age, sex, marital status and usual address). However they will be included in the non-response category for other applicable Census variables.

There are a number of reasons why person non-response occurs in the Census. People may indicate a desire to mail back a Census form or to complete the form online but may forget to do so, or some may have left the dwelling before form collection, and some people may refuse to complete a Census form.

For non-responding private dwellings, the count of persons, including non-responding, is based on a count obtained by the Collector. If not available, a count is imputed from the number of persons in similar dwellings in the area.

Note An 'other dwelling' in this context is a Non-Private Dwelling (NPD), or a dwelling in a Shipping, Off-shore or Migratory enumeration area. In other dwellings, the number of persons in each dwelling has already been established, as they are listed on a summary form by the dwelling manager or by a Special Collector. Due to their location, transitory or communal nature, it has traditionally been difficult to contact or obtain response from all those residing in these dwellings 'on the night', and non-response has been much higher than for private dwellings.

Table 1: Person non-response (a), 2011 Census, by state and territory
State/Territory Total Persons Non-responding persons % Non-responding persons
New South Wales 6,958,809 253,958 3.6
Victoria 5,351,225 170,077 3.2
Queensland 4,457,911 184,188 4.1
South Australia 1,593,577 41,112 2.6
Western Australia 2,278,155 108,343 4.8
Tasmania 489,029 11,235 2.3
Northern Territory 234,423 18,014 7.7
Australia Capital Territory 360,551 11,824 3.3
Total Australia (b) 21,727,160 798,826 3.7

  1. Based on Location on Census Night.
  2. Total Australia includes Other Territories.

Table 2: Person non-response (a), comparison between 2006 and 2011 Censuses, by state and territory
State/Territory 2006 2011 % Change
Count % Count % 2006 to 2011
New South Wales 285,060 4.3 253,958 3.6 -10.9
Victoria 178,752 3.6 170,077 3.2 -4.9
Queensland 184,085 4.5 184,188 4.1 0.1
South Australia 43,794 2.9 41,112 2.6 -6.1
Western Australia 100,971 5.1 108,343 4.8 7.3
Tasmania 12,749 2.7 11,235 2.3 -11.9
Northern Territory 17,627 8.1 18,014 7.7 2.2
Australia Capital Territory 12,073 3.7 11,824 3.3 -2.1
Total Australia (b) 835,328 4.2 798,856 3.7 -4.4

  1. Based on Location on Census Night.
  2. Total Australia includes Other Territories.

Item non-response

Item non-response consists of the total non-response for a Census variable that is applicable to those persons, and comprises persons included on a Census form but who did not answer the relevant question(s) for that variable. It also comprises those who were not included on a Census form (and were imputed) and for whom the question would have been applicable. The reasons relevant questions are not answered may be due to respondent fatigue, uncertainty, oversight, misunderstanding, or a perception that the particular question is not relevant to that person. For this reason, item non-response rates may vary for particular questions, for persons of different cultural backgrounds or for other characteristics such as age of the person.

Dwelling non-response

The dwelling non-response rate for the 2011 Census was 3.5%, compared with 4.2% in 2006, and reverses the trend for increasing dwelling non-response rates in previous Censuses.

Dwelling non-response occurs when a completed Census form has not been returned for a private dwelling which is believed to be occupied on Census Night. In recent Censuses, making contact and obtaining completed Census forms from householders has become increasingly difficult.

For the 2011 Census, improved procedures during enumeration and in processing were major contributing factors to the decrease in dwelling non-response. For example, Census Collectors being better able to identify dwellings that were unoccupied on Census Night, some of which may have otherwise been previously treated as occupied.

Table 3: Dwelling non-response, 2006 and 2011 Censuses, by state and territory
  2006 2011
State/Territory Total Dwellings Non-responding Dwellings % Non-response Total Dwellings Non-responding Dwellings % Non-response
New South Wales 2,470,498 111,704 4.5 2,599,231 93,755 3.6
Victoria 1,869,418 70024 3.7 2,031,293 64,721 3.2
Queensland 1,508,527 65,316 4.3 1,648,553 59,787 3.6
South Australia 609,943 18,038 3.0 643,902 16,306 2.5
Western Australia 758,048 37,470 4.9 851,406 35,286 4.1
Tasmania 189,078 4,916 2.6 199,878 4,461 2.2
Northern Territory 67,162 5,618 8.4 72,593 5,516 7.6
Australian Capital Territory 122,902 4,556 3.7 135,036 3,860 2.9
Total Australia (a) 7,596,369 317,655 4.2 8,182,707 283,735 3.5

  1. Total Australia includes Other Territories.