Census Undercount (cat no. 2940.0) provides the estimates of net undercount for the 2011 Census. It also includes information on how these estimates are calculated.
The information is obtained through a 2011 Census Post Enumeration Survey. It helps to determine how many people were missed and how many were counted more than once.
The estimated net undercount is used for the purpose of deriving population estimates for Australia, the states and territories.
It will be available June 2012 free from the ABS website.