EXPLANATORY NOTES
INTRODUCTION
1 This publication contains preliminary estimates on the travel movements of persons arriving in, and departing from, Australia.
2 A number of releases of Overseas Arrivals and Departures, Australia (cat. no. 3401.0) have been delayed due to passenger card processing issues as announced by the Department of Immigration and Border Protection (DIBP). Contingency processing plans are now in place to ensure the regular scheduled releases of these statistics can resume as soon as possible. For further information on the schedule for future release dates see the Notes Section of Overseas Arrivals and Departures, Australia, September 2014 (cat. no. 3401.0).
3 As part of the contingency plan, the ABS has produced some preliminary overseas arrivals and departure (OAD) estimates for January, February and March 2015 in this release. These preliminary OAD estimates have been modelled based on a combination of historical OAD data and information about travellers for the relevant reference months from DIBP's traveller processing system. For further information see the Estimation Model Method at Explanatory Notes 7 to 13.
4 The focus of this release is to provide some summary OAD estimates. It includes estimates for each category of movement by each state or territory of residence/stay and for Australia. The categories include short-term movements (i.e. less than one year), long-term movements (i.e. one year or more), and permanent movements. For those interested in overseas migration statistics, permanent and long-term movements in this publication are not an appropriate source. For information on Net Overseas Migration (NOM) refer to Migration, Australia (cat. no. 3412.0) and for quarterly NOM data refer to Australian Demographic Statistics (cat. no. 3101.0). Please note the estimates in this publication are a subset of the usual range of OAD statistics, and have not been seasonally adjusted. Final OAD statistics will be available in May 2015 in Overseas Arrivals and Departures, Australia (cat. no. 3401.0).
SOURCE OF THE STATISTICS
5 Travellers arriving in, or departing from, Australia provide information in the form of incoming and outgoing passenger cards (see Appendix 1). Travellers also provide information via passports and in visa applications (apart from people travelling as Australian or New Zealand (NZ) citizens). These, and other information available to DIBP, serve as a source for OAD statistics.
6 ABS statistics on OAD are calculated using administrative data collected and compiled by the Australian Department of Immigration and Border Protection (DIBP) under the authority of the Migration Regulations (Migration Act, 1958). The main source of data on overseas movements is usually incoming and outgoing passenger cards, which are matched with data from passports and visas. Information from these sources are usually collected, compiled and matched by DIBP and then stored with movement records on their Travel and Immigration Processing System (TRIPS). However, the processing of Australian passenger cards has been delayed for several months, with no passenger card data of sufficient quality being available since the September 2014 reference period. This has delayed the usual monthly releases of Overseas Arrivals and Departures, Australia (cat. no. 3401.0). In the interim, the ABS has modelled a subset of OAD statistics using traveller records from TRIPS. For further information see the Estimation Model Method at Explanatory Notes 7 to 13.
ESTIMATION MODEL METHOD
7 Due to the delayed release of the full set of monthly OAD statistics, caused by the delay in the processing of Australian passenger cards, the ABS has now modelled some preliminary OAD estimates for the months of January to March 2015. These modelled statistics are estimates of totals for each category of movement for each state or territory of residence/stay, and for Australia.
8 The model uses a one-year-ago propensity for passenger card data relative to movement data stored on TRIPS. The TRIPS movement data is the most up-to-date source available and is a strongly correlated data source compiled from administrative records such as passport and visa information that is managed by DIBP. To estimate the number of cards, the historical ratio of cards to TRIPS movements is used to scale the number of movements stored on TRIPS for each month. The ratio of cards to TRIPS movement data is very close to 1:1.
9 Key TRIPS variables such as Direction (Arrivals or Departures) and Visa type were used as correlates in the model to improve accuracy. The presence of this very strong correlating movements dataset makes an ideal candidate for modelling passenger card data. In addition, because TRIPS movement data is current, there is an expectation that the model will track behaviour strongly, even if this changes from past behaviour. Under ordinary operations when modelling is not required, passenger card records are linked to movement records on TRIPS to create the full set of monthly OAD statistics.
10 Despite some fluctuation from month to month, historical arrivals and departures time series of OAD statistics show a strong annual seasonality and a steady upward trend. The vast majority (96%) of arrivals and departures are short-term movements (i.e. less than one year), with long-term (i.e. one year or more) and permanent movements making a relatively small proportion at 4% of all movements.
11 The one-year-ago propensity is calculated separately for each month of the year, using only matching months from past years, eg the model for the current January data is based on the previous January one-year-ago. This ensures that the model reflects the seasonal patterns in OAD data. A number of averaging approaches were tested during investigations which compared historical TRIPS data with published OAD data. A review of comparison graphs over a 10-year time series, examining the strong seasonal pattern and the trend, confirmed the results and the strength of the one-year-ago propensity model.
12 For an estimate of accuracy, users can refer to the relative root mean square error (RRMSE) which can be used in a similar fashion to a relative standard error for sample surveys. The RRMSE is an estimate of accuracy for the modelled values, based on how well the model performs in comparison with known historical data. The ABS recommend using the RRMSE percentage to represent accuracy around projected data points for October 2014 and beyond. A 95% confidence interval can be formed by adding and subtracting 1.96 x RRMSE relative to the estimated count N.
13 Care should be taken by users as these are modelled estimates. The model assumes that seasonal and trend behaviour have remained consistent with recent history up to September 2014.
SCOPE
14 Overseas arrivals and departures statistics relate to all recorded movements of travellers who cross Australia's international border. The statistics record the number of movements of travellers rather than the number of travellers (i.e. multiple movements of an individual traveller during a given reference period are each counted separately). It includes the movements of all travellers regardless of their nationality, citizenship or legal status.
15 The statistics exclude the movements of operational air and ships' crew, of transit passengers who pass through Australia but are not cleared for entry (including some defence force personnel), and of passengers on pleasure cruises commencing and finishing in Australia. These statistics also exclude undocumented arrivals or departures.
STATE AND TERRITORY CLASSIFICATION
16 Following the 1992 amendment to the Acts Interpretation Act to include the Indian Ocean Territories of Christmas Island and the Cocos (Keeling) Islands as part of geographic Australia, population estimates commencing with September quarter 1993 include estimates for these two territories. To reflect this change, another category of the state and territory classification has been created, known as Other Territories. Other Territories includes Jervis Bay Territory, Christmas Island and the Cocos (Keeling) Islands. OAD data for Other Territories are not available prior to February 1995.
CONFIDENTIALITY
17 The Census and Statistics Act, 1905 provides the authority for the ABS to collect statistical information, and requires that statistical output shall not be published or disseminated in a manner that is likely to enable the identification of a particular person or organisation. This requirement means that the ABS must take care and make assurances that any statistical information about individual respondents cannot be derived from published data.
18 Some techniques used to guard against identification or disclosure of confidential information in statistical tables are suppression of sensitive cells, random adjustments to cells with very small values and rounding. In these cases data may not sum to totals due to the confidentialisation of individual cells.
ROUNDING
19 The estimates in this publication have been rounded to the nearest 100. Where figures have been rounded, discrepancies may occur between sums of component items and totals. Analysis featured in the Key Points and Main Features of this publication is based on un-rounded data. Calculations made on rounded data may differ to those published.
RELATED PRODUCTS
20 Users of these statistics may also wish to refer to the following ABS products:
21 Recent publications released by the National Migration Statistics Unit (ABS) include:
22 Related statistics are also published by:
23 As well as the statistics included in this and related publications, additional demographic information is available on the ABS website, <
https://www.abs.gov.au>; click
Topics @ a Glance, then under People click on
Demography. Users can also access the full range of electronic ABS data free of charge on the ABS website.
24 The ABS also issues a daily
Release Advice on the website which details the products to be released in the week ahead.
ACKNOWLEDGMENTS
25 This publication draws extensively on information provided by the Australian governments Department of Immigration and Border Protection (DIBP). The ABS also uses information provided freely by individuals, businesses, governments and other organisations. Their continued cooperation is very much appreciated; without it, the wide range of statistics published by the ABS would not be available. Information received by the ABS is treated in strict confidence as required by the
Census and Statistics Act 1905.
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