Overseas Arrivals and Departures, Australia methodology

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Reference period
January 2023
Released
15/03/2023

Introduction

1. This page provides a reference of the various methods and changes that occur from time to time that may impact the quality of OAD statistics. Changes can be due to any part of the end-to-end processing, from passenger data collection to the output of OAD statistics. They can range from the design, provision and collection of the passenger cards through to the administrative systems and updates at Home Affairs. They can also result from better capture of passenger data, methodological improvements or improved processing systems.

Abbreviations

ABSAustralian Bureau of Statistics
ACTAustralian Capital Territory
ARIMAAuto-regressive integrated moving average
Aust.Australia
COVID-19Coronavirus disease 2019
DIBPAustralian Government Department of Immigration and Border Protection
Educ.Education
ERPEstimated resident population
GFCGlobal Financial Crisis
GSTGoods and Services Tax
Home AffairsAustralian Government Department of Home Affairs
IPCIncoming passenger card
LTRDLong-term resident departure
LTRRLong-term resident return
LTVALong-term visitor arrival
LTVDLong-term visitor departure
MEDBMedicare Enrolments Database
nanot available
necnot elsewhere classified
nfdnot further defined
NOMNet overseas migration
NSWNew South Wales
NTNorthern Territory
NZNew Zealand
OADOverseas arrivals and departures
OPCOutgoing passenger card
PAPermanent arrival
PNGPapua New Guinea
QldQueensland
ROADSRebuild of the OAD system
SASouth Australia
SACCStandard Australian Classification of Countries
SARSpecial Administrative Region
SARSSevere Acute Respiratory Syndrome
STRDShort-term resident departure
STRRShort-term resident return
STVAShort-term visitor arrival
STVDShort-term visitor departure
Tas.Tasmania
TRIPSTravel and Immigration Processing System
Unit Arab EmirUnited Arab Emirates
UKUnited Kingdom, Channel Islands and Isle of Man
USAUnited States of America
Vic.Victoria
WAWestern Australia

Classifications

Country

State and territory

Confidentiality

1. The Census and Statistics Act, 1905 provides the authority for the ABS to collect statistical information, and requires that statistical outputs shall not be published or disseminated in a manner that is likely to enable the identification of a particular person or organisation.

2. 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.

3. The statistics in this release have been rounded to the nearest 10 to maintain confidentiality. Where figures have been rounded, discrepancies may occur between sums of component items and totals. All calculations and analysis are based on un-rounded data. Calculations made on rounded data may differ to those published.

Data sources

1. Administrative information on persons arriving in, or departing from, Australia is collected via various processing systems, passport documents, visa information, and incoming passenger cards (see Passenger card image section). Aside from persons travelling as Australian or New Zealand citizens, persons travelling to Australia are required to provide information in visa applications. These administrative data are collected by the Home Affairs under the authority of the Migration Regulations 1994 made under the Migration Act 1958.

2. ABS statistics on overseas arrivals and departures (OAD) are mainly compiled using information from Home Affairs sources. All overseas movement records are stored on Home Affairs' Travel and Immigration Processing System (TRIPS). Each month all OAD movement records and related information, including those matched to an incoming passenger card, are supplied to the ABS and then processed.

3. From July 2017, due to the removal of the outgoing passenger card, the ABS has also used Medicare enrolment data. This is a secondary source of state or territory of residence information for Australian residents and is used for a small proportion of records. For further information see ABS Privacy Impact Assessment Report 'Traveller Information and Medicare Enrolment PIA' released on the 12 September 2017. 

Glossary

Details

History of changes

1998

1999

2001

2004

2007

2013

2014

2016

2017

2018

2019

2020

2021

2022

Imputations and derivations

1. Every effort is made to minimise errors, both through careful design of the passenger cards and through checks on the information once it is received by the ABS. During the editing process some items are corrected where they conflict with other known information. There are a number of derivations and imputations undertaken that improve the quality of variables with missing responses.

2. First, the ABS utilises alternate sources where available. The sources currently available from Home Affairs include: all overseas movements data stored on the TRIPS system, monthly missing country of birth data, and monthly New Zealand passport data. An additional alternate source used for state or territory of residence is Medicare enrolment data - see 'state or territory of stay/residence' in the 'List of variables imputed' below.

3. For certain variables that are missing, information about an individual can be derived from these alternate sources including an individual's nearest other travel movement. This is able to be done from Home Affairs sources, by using the unique person identification number to link to the various sources and over time. For example, by accessing all movements stored on the TRIPS system, the ABS is able to make use of information from a corresponding incoming passenger card to acquire information about an individual's departure movement. Pre-reference date data includes all previously processed historical records, whereas the post-reference date data includes all TRIPS records up to and including 27 days after the end of the reference month.

4. The variables which are available from accessing these alternate sources include: country of birth, country of citizenship, country of residence/stay, duration of stay, passenger card box type, and state of residence/stay.

5. Second, a 'hot deck' imputation method is then used for any remaining missing responses. For 'hot deck' imputation, a record with missing responses (called the recipient), receives those of another similar record (called the donor) which has a full set of responses before the imputation process began. The recipient record keeps all of its original responses and only has the missing variables imputed, thereby keeping as much of the collected information for that record as possible.

6. The 'hot deck' imputation method uses a set of characteristics that choose the donor and recipient records which are as similar as possible. The characteristics used within the OAD system to align a recipient with a suitable donor, vary between the different imputations. A combination of different characteristics was tested for each of the imputations to ascertain which would give the best results. The characteristics used include: age, country of birth, country of citizenship, country of residence/stay, direction of traveller, category of movement, passenger card box type, sex, state of clearance and visa group.

7. The variables which are subject to 'hot deck' imputation are: age, country of birth, country of citizenship, country of embarkation, country of residence/stay, duration of stay, passenger card box type, reason for journey, sex and state of residence/stay, and a specific one for the country of birth of New Zealand (NZ) citizens. All missing values for these variables are fully imputed except country of residence/stay for permanent arrivals. However, from July 2017, due to the removal of the outgoing passenger card, the following are not imputed: country of disembarkation for any departures and country of stay for any Australian resident departures as both are no longer collected.

List of variables imputed

Specific imputation for country of birth of New Zealand citizens

Passenger card images

Incoming card - front

Incoming card - back

Provisional estimates

1. From June 2021 this publication contains some provisional statistics on the international travel movements of persons arriving in, and departing from, Australia.

2. This additional data is being included in response to COVID-19 and the heightened interest in traveller data. The data does not incorporate arrival card information and the use of other administrative data. The data is provisional and has not had the full quality assurances applied during the standard processes normally undertaken for Overseas Arrivals and Departures (OAD).

Provisional statistics compared with OAD statistics

3. Data from the Travel and Immigration Processing System (TRIPS) is the main data source for both the regular monthly OAD data and the additional provisional data. The provisional data is used in its raw form. The ABS makes no alterations, imputations or logical edits to this data. No adjustments are made for missing data items.  The provisional data are unable to be broken down by short-term movements and long-term movements, as occurs in the regular monthly OAD data.

4. However, because they are based on the same main data source, top level data in the Overseas Arrivals and Departures collection and the provisional estimates  are very closely aligned. The comparison is shown in Figure 1 (All Arrivals) and Figure 2 (All Departures).

State and territory of clearance

5. State and territory of clearance is based on the international airport or sea port of clearance whereby an international traveller is cleared by Australia's Border Force. Users should take care not to confuse this with state and territory of residence/stay. For more information, see the Glossary.

Sampling

1. OAD statistics are usually derived from a combination of full enumeration and sampling. All permanent arrivals and all arrivals with a duration of one year or more (long-term arrivals) have always been fully enumerated. From July 2007, all departures have been fully enumerated. From April 2020 to February 2022, full enumeration was undertaken for all arrivals, due to the small volume of international travel movements caused by international travel restrictions. Sampling was reintroduced from 1 March 2022 for arrivals of trips of less than one year (short-term arrivals). The travel volumes are being monitored by the ABS and the sample of short-term arrivals is being updated as volumes continue to increase.

2. All arrivals with a duration of less than one year (short-term arrivals) were sampled. While the total number of travellers and their citizenship was fully known, statistics for other characteristics of short-term arrivals (such as their state/territory of stay/residence) were based on a sample and may differ slightly from those that would be obtained from complete processing. The sample was a fixed skip based on a threshold selected by country of citizenship. The sample was designed so that countries of citizenship associated with a small number of movements were fully sampled, while countries with a larger number of movements tended to have a higher threshold. This approach minimised the effect of sampling error associated with the available statistics. When the threshold was reached, the passenger card was selected and data extracted. For example, prior to April 2020, every 55th short-term Australian arrival card was selected and the data extracted and fully quality assured for that specific card, while every single passenger card for a traveller with Sierra Leone citizenship would be selected. From July 2007 to April 2020, about 5% of all short-term arrivals were selected for sample.

3. Some statistics relating to these movements are therefore estimates which are subject to sampling variability, that is, they may differ from statistics which would have been obtained if details of all these movements had been processed. The sampling error associated with any estimate can be estimated from the sample results and one measure so derived is the standard error. It would be impractical however, to publish estimates of standard errors for all figures from OAD statistics in individual tables.

Scope

1. This release contains traveller movement data which should not be interpreted as 'persons'. 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.

2. 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.

3. From 1 July 2016, Norfolk Island was integrated into Australia for administrative purposes. Travel between Australia and Norfolk Island is no longer considered an international movement and is therefore not included in Overseas Arrivals and Departures statistics.

4. The focus of this release is information and analysis of short-term movements (i.e. less than one year), in particular short-term visitor arrivals (STVA) and short-term resident returns (STRR). Permanent and long-term movements in this publication are not an appropriate source of migration statistics. For further information refer to:

5. These statistics are important as input to a broad range of other statistical collections, including:

  • Australia's official population estimates, through estimates of Net Overseas Migration (NOM);
  • the Australian Migration Planning Framework;
  • key national economic and tourism indicators;
  • forecasting NOM into the future;
  • International Trade & Balance of Payments statistics;
  • compiling the International Accounts and the Tourism Satellite Account;
  • estimating National Income and Consumption; and
  • creating benchmarks for the International Visitors Survey.

Seasonally adjusted and trend estimates

1. Trend estimates have been suspended from February 2020 and seasonally adjusted estimates have been suspended from April 2020 due to the impact of the COVID-19 pandemic on international travel. Please see 2020 under the History of changes section.

2. Seasonally adjusted estimates are derived by estimating and removing systematic calendar-related effects from the original series. In the short-term visitor arrival and short-term resident return series, these calendar-related effects include seasonal (e.g. increased travel in December due to the Christmas holiday period), moving holiday (e.g. increased travel in January in some years and February in others due to Lunar New Year celebrations) and trading day influences (arising from the varying length of each month, the composition of the days of the week in a month, and the varying levels of activity for different days of the week). Each influence is estimated by separate factors which, when combined, are referred to as the combined adjustment factors.

3. For March 2020, seasonal factors for both the short-term visitor arrival and short-term resident return series were calculated using data up to and including February 2020, then forecast for March 2020. This approach, known as the forward factor method, ensures that the seasonal factors are not distorted by COVID-19 impacts. The forward factor method of seasonal adjustment uses data up to a fixed point in time to estimate seasonal factors. These factors are then forecast to provide seasonal factors for the next 12 months. This process is repeated annually to calculate seasonal factors for the coming year. Seasonal factors for previous years are also revised at this point. This method has been used in the past, and was in use until June 2003 (as described below) when it was superseded by the Concurrent seasonal adjustment method.

4. From August 2019, the ABS improved the method for calculating trend estimates. It changed by removing the "ripple" effects, which tend to be more inherent in the previous trend series for smaller series and lower level estimates. The result of removing these "ripple" effects is trend estimates which are less volatile and less prone to revisions over time. An article prepared for the March 2018 issue of Labour Force, Australia (cat. no. 6202.0) explaining the new method can be accessed here: Improvements to Trend Estimation

5. From July 2007, the ABS improved the method of producing seasonally adjusted estimates, focusing on the application of ARIMA modelling techniques, which can improve the revision properties of the seasonally adjusted and trend estimates. For more information on the details of ARIMA modelling, see 'Feature article: Use of ARIMA modelling to reduce revisions' in the October 2004 issue of Australian Economic Indicators.

6. From November 2004, the ABS improved the method for removing trading day effects from seasonally adjusted estimates. Corrections for trading day effects are now applied as prior corrections to the original estimates, rather than being applied within the seasonal adjustment process. This is now consistent with the treatment of any corrections for large extremes, changes in level, changes in seasonal pattern, Easter, and other effects.

7. From July 2003, concurrent seasonal adjustment methodology was used to derive the combined adjustment factors. This means that data from the current month are used in estimating the combined adjustment factors for the current and previous months. Concurrent seasonal adjustment replaces the forward factor methodology used since seasonal adjustment of short-term visitor arrivals began in 1969 and short-term resident departures in 1976.

8. Concurrent adjustment can result in revisions each month to the seasonally adjusted estimates for earlier periods. However, in most instances, the only noticeable revisions will be to the combined adjustment factors for the current month, the previous month and the same month a year ago. Although there is no specific information paper on concurrent adjustment to short-term visitor arrivals or resident departures, more detail on the method in general can be found in the Information Paper: Introduction of Concurrent Seasonal Adjustment into the Retail Trade Series (cat. no. 8514.0).

9. An improved correction method has been implemented in the seasonal adjustment process to remove the effects of Lunar New Year, Ramadan, Diwali and Easter from the seasonally adjusted estimates:

  • Lunar New Year - Lunar New Year often falls in February but on some occasions falls in January. The seasonally adjusted and trend estimates for January and February should account for the impact of the calendar-related effect associated with the movement of Lunar New Year between the boundary of January and February. The Lunar New Year proximity adjustment method takes into account the change in activity before, during and after the event, with the size and shape of this effect depending on the series. In some series, the proximity correction is only applied to part of the series, as it is not significant for the entire series. Further details on this adjustment method can be found in 'Estimating and removing the effects of Lunar New Year and Ramadan to improve the seasonal adjustment process' in Australian Economic Indicators (cat. no. 1350.0, November 2005 issue).
  • Ramadan - Ramadan is the ninth month of the Islamic calendar and starts eleven days earlier each year in the Western calendar, so adjustments for this effect apply to different months over the years. The adjustment was made after the detection of a significant influence on travel for Malaysia, Indonesia and several North African and Middle Eastern countries associated with the start and/or end of the Islamic month of Ramadan. The estimates for Total South-East Asia and Total North Africa and the Middle East were also corrected as a consequence of these corrections. Other time series did not have a significant Ramadan effect and were not corrected.
  • Diwali - Diwali marks the beginning of the Hindu New Year and is celebrated in autumn (northern hemisphere) or spring (southern hemisphere) every year. An adjustment was made after the detection of an influence on visitor arrivals from Singapore.
  • Easter - Easter falls on the Sunday after the ecclesiastical Full Moon that falls on or after March 21. It is therefore observed between late March and late April. Adjustments were made to movements from a number of countries.
     

10. Seasonal adjustment procedures do not aim to remove the irregular or non-seasonal influences which may be present in any particular month, such as the effect of major sporting and cultural events, changes in airfares and the fluctuation of the Australian dollar relative to other currencies. Irregular influences that are highly volatile can make it difficult to interpret the underlying movement of the series even after adjustment for seasonal variation. Trend estimates take these irregular influences into account.

11. Trend estimates for short-term overseas visitor arrivals and short-term Australian resident returns are derived by applying a 13-term Henderson weighted moving average to all months of the respective seasonally adjusted series (after correcting the series for large extremes or changes in level) except the ends. A different set of specially designed Henderson moving averages are applied to the initial and last six months where the 13-term version cannot be used due to a lack of data points. While this technique enables smoothed data for the latest period to be produced, it does result in revisions to the smoothed series, principally of recent months, as additional observations become available. There may also be revisions as a result of the re-estimation of the seasonal factors. For further information, see A Guide to Interpreting Time Series - Monitoring Trends (cat. no. 1349.0) and Time Series Analysis Frequently Asked Questions (cat. no. 1346.0.55.002).

12. Under concurrent seasonal adjustment, the most recent seasonally adjusted and trend estimates are likely to be revised when estimates for subsequent months become available. The trend revision is a combined result of the revision of the seasonally adjusted estimates and the revision derived from the use of asymmetric moving averages as future data become available. ABS research shows that about 75% of the total revision to the trend estimate is due to the use of different asymmetric moving averages when the estimate for the next time period becomes available. To assess the reliability of the trend estimate, the 'what-if' charts present trend estimates under two different scenarios for the next time period. The charts show only the impact due to the changes of the asymmetric moving averages and do not include the unknown impact of revision to seasonal factor estimates that would arise when the estimate for the next time period becomes available.

13. Occasionally situations occur that necessitate breaks being applied to the trend series. These breaks are necessary because of a change in the underlying level of the series. While the breaks apply to an individual country (e.g. Pakistan), a consequence is that breaks are also applied to the regional total series (e.g. Total Southern Asia) and the Total series.

14. Trend breaks currently included in the STVA and STRR trend series are as follows:

STVA

  • Fiji - June 2000: decrease in STVA movements - Coup in Fiji
  • Indonesia - December 1997: decrease in STVA movements - Asian Financial Crisis
  • Korea - December 1997 and January 1998: decrease in STVA movements - Asian Financial Crisis
  • Other North Africa and the Middle East - September 2003: Increase in STVA movements - Gulf War
  • Pakistan - April 2016: increase in STVA movements - suicide bombing attack on 27th March, major floods on 3rd April, and earthquake on 10th April
  • Poland - November 2002: decrease in STVA movements
  • Sweden - September 2008: decrease in STVA movements - Global Financial Crisis
  • Thailand - August 1997: decrease in STVA movements - Asian Financial Crisis
     

STRR

  • Fiji - July 2009: increase in STRR movements - Additional flights available direct to Fiji from Melbourne and Adelaide
  • Turkey - March 2016: decrease in STRR movements - Ankara suicide bombing attack
  • Japan - April 2011: decrease in STRR movements - Fukushima earthquake
     

15. For a detailed discussion and analysis of OAD time series estimates, see the ABS Demography Working Paper 2004/2 - Interpretation and Use of Overseas Arrivals and Departures Estimates (cat. no. 3106.0.55.002).

16. For information looking at the implications of unusual external events on ABS time series, see the ABS Feature Article: When It's not "Business-as-usual": Implications for ABS Time Series (cat. no. 1350.0 for Aug 2009).

Technical note - seasonally adjusted and trend estimates

Statistics and variables available

ABS products

1. The ABS may have other relevant data available on request. Generally, a charge is made for providing this information. Inquiries should be made to the National Information and Referral Service on 1300 135 070.

2. The following variables for overseas arrivals and departures data are available on request:

  • Age
  • Category of movement (e.g. permanent arrival, short or long-term visitor arrival, short or long term resident return, short or long-term visitor departure, short or long term resident departure)
  • Country of birth
  • Country of citizenship (nationality)
  • Country of embarkation
  • Country of residence/stay - only available for arrivals (e.g. for a visitor arriving their country of residence, for resident returning their country of stay)
  • Direction - arrival or departure
  • Duration of stay (i.e. actual time spent in or away from Australia, for visitors arriving it is based on intended length of stay)
  • Main reason for journey - only available for arrivals (not available for permanent arrivals)
  • Mode of transport (air or sea)
  • Port of clearance (i.e. the air or sea port where a traveller is cleared for international travel by the Australian Border Force)
  • Reference day/date
  • Reference month
  • Reference year (available back to 1976)
  • Sex
  • State or Territory of clearance (i.e. the state or territory where a traveller is cleared for international travel by the Australian Border Force)
  • State or Territory of residence/stay (i.e. for a resident the state/ territory where they live or will live, for a visitor their state/ territory of stay)
  • Visa applicant type - primary or secondary (available from July 2004)
  • Visa subclass (available from July 2004)

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