POPULATION TURNOVER
Introduction
Migration is recognised as a key factor in regional social and economic development. The Information Paper: Regional Research in Australia - the Statistical Dimension: an Information Development Plan for Rural and Regional Statistics, 2005 (cat. no. 1362.0) identified a need for data on the movement of people into and out of regions to inform regional research and policy themes. Inter-regional migration impacts broadly on a range of issues such as the size and structure of inter-regional labour markets, the demand for services, and the human capital that contributes to community strength.
Official statistics regarding Australia's demography - such as those released under the Estimated Resident Population (ERP) conceptual framework - do not contain precise estimates of the components of internal and overseas migration at the Statistical Local Area (SLA) geographic level. As a result, there are no official statistics regarding SLA rates of population turnover - a phenomenon of interest to policy makers and service providers alike and one which can be hidden when only looking at data relating to population estimates themselves.
Population turnover estimates measure the rate of gross moves (i.e. the number of people moving into an area plus the number of people moving out) in relation to the size of the population. Population turnover is different from population growth, which is the net change in population. It is quite possible, for example, for an area to have its population estimate remain virtually unchanged from one period to the next, but for many of its current residents to be different people than those who were residents in the previous period.
Population turnover estimates are therefore of strong interest because they can help understand, for example, why the characteristics and needs of a region are changing significantly within the context of having a relatively stable population count.
In response to this interest, estimates of this phenomenon have been produced using some of the vast amount of information able to be extracted from the Census of Population and Housing (Census) conducted every five years by the Australian Bureau of Statistics (ABS). 2006 Census usual resident data was used to outline the extent of population turnover across Australia at the SLA geographic level, between August 2001 and August 2006, and to illustrate some of their particular demographic characteristics.
Structure of the release
Census data are used firstly to create estimates of population turnover at the SLA geographic level. SLAs are then ranked according to these estimates, and other Census data are then used to identify any similarities in the characteristics of the twenty highest and twenty lowest turnover SLAs. This analysis is described and summarised in the chapter titled Statistical Local Areas in Australia.
For information about population turnover in the SLAs not shown in the top or bottom twenty, please refer to the Excel spreadsheet in the Downloads tab.
Following this are separate chapters for each state and territory. In these chapters, the jurisdiction's five highest turnover SLAs are identified and one of these SLAs is explored using other dimensions of the Census data. The individual SLA explorations illustrate how Census data can be used to investigate differences in the characteristics of people arriving in, departing from, and staying in a particular SLA. It is this analysis that allows users to start to understand more deeply changes in the characteristics of their region of interest that may be attributable to migration.
The detailed data shown for these eight SLAs in the state and territory chapters is not included in the accompanying Excel spreadsheet. For detailed data about the characteristics of other regions as illustrated in these chapters, please contact the National Information and Referral Service on 1800 135 070.
A note of caution
The strength of the Census data is that it enables the construction of small area estimates, such as at the SLA level, but this strength does come at a cost. In this case the cost relates to the necessary adoption of different conceptual bases than would be used to create official estimates within the ERP conceptual framework. The main conceptual differences regarding scope are that the Census-based population turnover estimates released in this publication exclude people who are included in the ERP numbers, namely: people under 5 years old at the time of the 2006 Census; and residents temporarily overseas.
In addition to these scope differences, the Census-based population turnover estimates released in this publication have been constructed using information relating only to those people who stated where they lived five years ago when they completed the 2006 Census questionnaire (i.e. migration status has not been imputed for people who did not state where they lived five years ago when they completed the 2006 Census questionnaire).
In some SLAs the exclusions noted above were relatively large. In these cases the adjusted Census count used in the population turnover calculation was very different than the 2006 Census count. For example, the New South Wales SLA of Sydney (C) - Inner has been estimated to have a population flow of 12,335 people with a turnover rate of 98.6%. This implies an adjusted 2006 Census count of 12,510 people, meaning that 9,477 of the actual 2006 Census count have been excluded on one basis or another (e.g. being under five years old, or not stating their previous address).
Finally, the estimates regarding people departing from an SLA exclude any information about people who (at the time of the 2006 Census) no longer lived in Australia. This is because these people are not enumerated as part of the Census.
As a result, users need to be aware that all of these estimates contain biases of varying extent (for example, in that they do not contain information about the characteristics of those who did not state where they lived five years ago) and that this degree of bias needs to be taken into account when thinking through the possible implications of these estimates for an SLA of interest. Further details about the terms and concepts used in this publication can be found in the Explanatory Notes and Glossary.
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