THE IMPORTANCE OF EFFECTIVE STATISTICAL INDEPENDENCE
1 The PES is designed to be a robust and independent measure of Census coverage. Therefore, it is critical that the statistical independence between the PES and the Census is effectively managed.
2 There are two aspects to statistical independence, both of which were effectively managed throughout the 2016 PES cycle: population independence and operational independence.
3 Population independence refers to the principle that there should be no subgroups of the population where being missed in the Census indicates that a person or dwelling is also more likely to be missed by the PES. In practice, some population subgroups may be less likely to respond to both the Census and the PES. Although the PES estimation process adjusts for this to some extent, by subdividing the population into smaller groups where the assumption of population independence is more likely to be true, population independence is always more difficult to achieve than operational independence.
4 Operational independence requires that Census operations do not influence the PES in any way, and vice versa. The operational independence of the PES from the Census was effectively monitored at every stage of the 2016 cycle, including enumeration, processing and administration. Steps taken to ensure this independence included:
- selecting the PES sample from an independent sample frame
- using separate office staff in the PES and Census
- ensuring PES interviewers were not employed as Census Field Officers in the same area
- maintaining the confidentiality of the PES sample so Census field and office staff were unaware of which areas were selected in the PES
- using a separate and secure information technology environment for processing the PES data
- ensuring Census forms received after PES enumeration commenced (i.e. late returns) were excluded from PES estimation. For more information, see Components of Net Undercount on the Summary tab.