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ABS DATA SOURCE, DEFINITIONS AND DATA LIMITATIONS

The data used in this article are based on final NOM data from the ABS analytical Travellers' Characteristics Database and covers the 2004-05 to 2008-09 financial year period. An individual's actual travel behaviour and associated characteristics are only available from final NOM data, as these details can only be accurately recorded at the end of a 16 month reference period following a traveller's initial border crossing.


'12/16 month rule' methodology for NOM

Internationally, NOM is defined on the net gain or loss of population through immigration to a country (NOM arrivals) and emigration from a country (NOM departures), based on an international traveller's duration of stay being in or out of that country for 12 months or more.

Australia's official ERP applies a '12/16 month rule' for calculating NOM and counts any traveller who is in Australia for a total of 12 months or more over a 16 month period, or conversely, excludes from ERP a traveller who is out of Australia for a total of 12 months or more over a 16 month period. It should be noted that NOM data based on the '12/16 month rule' methodology were not used in Australia's official population counts until September quarter 2006.

All ABS data for NOM in this article are based on the current '12/16 month rule' methodology for calculating NOM. NOM estimates on this basis are only available from December quarter 2003. Further information on this methodology and the reasons for the change in method can be found under the Explanatory Notes tab, available with the electronic release of Migration, Australia, 2008-09 (cat. no. 3412.0) in the Technical Note -'12/16 month rule' Methodology for Calculating Net Overseas Migration from September quarter 2006 and onwards. For further information on NOM arrivals; NOM departures; the '12/16 month rule'; or ERP see the Glossary attached to this publication.

Student NOM is the net gain or loss of population through persons immigrating to Australia on a temporary student visa (student NOM arrivals) or emigrating from Australia on a temporary student visa (student NOM departures). As with total NOM, it is based on an international traveller's duration of stay being in or out of Australia for 12 months or more.


Data limitations

It is important to note that the majority of analysis on ABS data in this article refers to the net contribution to population change of persons travelling on temporary student visas. The net contribution is the difference between NOM arrivals and NOM departures in a reference period for persons holding a temporary student visa at the time of arrival or departure. This is shown as the student net overseas migration figure throughout the article (i.e. student NOM).

Not all persons arriving on a student visa will leave on a student visa, as on the completion of a course, a student may apply for another visa and depart Australia on that visa. For example, after completing their studies a student may apply for an onshore permanent residence visa; another student visa; or another visa such as a bridging or temporary business long-stay (subclass 457) visa. Therefore, some students may change their visa and residency status whilst onshore. In these instances, the original student visa recorded as a student NOM arrival now changed to a new visa or residency status and will not be recorded as a corresponding student NOM departure for this particular traveller. A traveller's NOM departure is not recorded until the traveller has left Australia and has remained away for 12 months or more in the 16 month reference period. It is only at this stage that the NOM system will record the change of visa by a traveller. Care should therefore be taken with student visas when analysing the net figure (i.e. student NOM) on its own.

In instances where former student visa holders do not depart Australia at the end of their course but apply for new visas, some apply for and are issued with another student visa. Data from DIAC for the six months ending December 2010 indicates that 56,800 visas were granted (most being onshore applications), where the last visa held was a student visa(footnote 1) . Of these visa grants, 30% of previous students were issued with another student visa, 25% were issued with tourist visas and a further 16% were issued with graduate-skilled visas. The comparative proportions for the six months ended December 2009 were 29%, 26% and 17% respectively.

The net contribution of student arrivals and departures is also seasonal. The peak in student NOM occurs in the March quarter and, to a lesser extent, in the September quarter, the traditional start of education courses in Australia. The low point in student NOM occurs in the December quarter, the traditional end of study courses in Australia. The seasonality of student arrivals and departures is clearly evident in figure 6.2. Also evident is the strong impact that students have on NOM, with quarterly NOM mainly rising and falling in line with the flows of international students.

6.2 NOM(a), Student visas(b) - Australia - Sep Qtr 2004 to Jun Qtr 2009