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Introduction
Background
Summary of results
Evaluation criteria
Medicare Australia data
Taxation data
Australia Post data
School enrolment data
Driver licence data
Australian electoral roll data
Electricity connections data
Data sources evaluated in 1996 and 2001
Summary of all evaluations
Bibliography


INFORMATION PAPER


1. INTRODUCTION

This report evaluates the suitability of a number of administrative data sources for use in the quarterly estimation of interstate migration for the period 2006-2011. It is an update of Demography Working Paper 2001/5 - Evaluation of Administrative Data Sources for Use in Quarterly Estimation of Internal Migration Between 2001 and 2006 (cat. no. 3127.0). The report consists of seven main sections covering the following potential data sources:

• Medicare Australia data;
• Taxation data;
• Australia Post data;
• School enrolment data;
• Driver licence data;
• Australian electoral roll data; and
• Electricity connections data.

• a description and background of the potential data source;
• a table that outlines the results of the assessment of the data source against a number of key criteria; and
• recommendations.

Table 1 Evaluation Criteria
Criteria	Ideal Data Characteristics	Minimum Data Characteristics
Population and coverage	All usual residents of Australia.	Complete subsets of usual residents, e.g. persons aged 65 and over.
Data content	Individual record data relating to age (date of birth), sex, date of move, origin and destination.	Personal details plus net interstate migration plus reference quarter indicative.
Geographic level	Data at the Statistical Division level or below.	State level data.
Timeliness and periodicity	Data released within one month after the end of the reference quarter showing quarterly movements.	Data released four months after the end of the reference quarter showing quarterly movements.
Historical availability	Data available from 1st July 2001 to allow comparison with revised intercensal migration estimates for 2001-2006 (based on 2006 census results).	Data available from 1st July 2005 to allow for comparison with 2005-06 interstate migration data.
Consistency	No data definitional changes over time.	Data definitional changes which can be quantified.
Electronic capture	Current data and past data available in Comma Separated Value (CSV) format.	Current data available in some electronic format.

• they hold Australian citizenship;
• they hold New Zealand citizenship;
• they have been issued with a permanent residence visa; or
• they have applied for a permanent residence visa and have:
  • permission to work in Australia; or
  • a parent, spouse or child who is an Australian citizen or permanent resident;
  • however, restrictions apply to persons who have applied for a parent visa (other requirements apply).

Table 2 Assessment against Evaluation Criteria(a), Medicare Australia data
Criteria	Assessment
Population and coverage	Suitable:
	In 2004, there were approximately 21 million clients enrolled in the Medicare scheme holding approximately 12 million cards. The Medicare database covers all usual Australian residents excluding foreign diplomats and their families. This includes non-Australian residents who are granted temporary eligibility such as academics, skills transfer employees and those in the Various Contributory Parent Visa Category of Medicare.
	The coverage of children is enhanced by the National Childhood Immunisation Register (a subset of the Medicare register).
Data content	Suitable:
	Medicare data includes unit record change of address details as well as sex and date of birth (from which age can be calculated).
Geographic level	Suitable:
	Postcode level data provide sufficient geographic information.
Timeliness and periodicity	Suitable:
	Data are available on the 7th working day after the end of the reference quarter showing quarterly movements.
Historical availability	Suitable.
Consistency	Suitable:
	Consistency is acceptable. However there have been some inconsistencies in the 1990s relating to card re-issue schemes. A system change in February of 2004 also resulted in some minor inconsistencies.
Electronic capture	Suitable:
	Data are available in CSV format.
(a) Refer to Table 1

Table 3 Assessment against Evaluation Criteria(a), Taxation data
Criteria	Assessment
Population and coverage	Unsuitable:
	The sub-population is all persons in Australia who submit tax returns (and their spouses/partners) to the ATO for two consecutive years. This mainly covers the working age group (persons aged 15-64 years).
	Change of address details are not captured for dependent children and there is only limited coverage available for those persons aged 65 years and over. The population also covers significantly more males than females in most age groups.
Data content	Unsuitable:
	Taxation data include change of address details. However, because substantial coverage of tax returns is only available 12 months after the end of the financial year, age of movers can only be approximated within a two year period as the exact date an individual moved is unknown. Data are limited to those individuals who complete a tax return over two consecutive years.
	The change of address details in a small proportion of tax returns are deemed invalid due to individual/agent recording errors in the date of birth and/or postcode section.
Geographic level	Suitable:
	Postcode level data allow for sufficient geographic information.
Timeliness and periodicity	Unsuitable:
	There is a significant lack of timeliness. Using this data would mean that estimates of interstate migration would be lagged by more than one year.
	The data are only produced annually making it unsuitable for the ABS' quarterly estimations of interstate migration.
Historical availability	Suitable:
	Taxation change of address data are available from 2001 and prior to that if needed.
Consistency	Suitable.
Electronic capture	Suitable:
	The data could be captured in some electronic format.
(a) Refer to Table 1

Table 4 Assessment against Evaluation Criteria(a), Australia Post data
Criteria	Assessment
Population and coverage	Unsuitable:
	The population of the Australia Post address change database is all people with an active redirection notice and other members of the household who are nominated on that notice.
	Comparisons with ABS estimates of interstate movement, which are based on address changes advised to Medicare, indicate that significantly less movers are represented in the Australia Post database than ABS estimates. In addition, the ABS has reservations on how representative these data are.
Data content	Unsuitable:
	The database contains geographic indicators of origin and destination addresses, but does not contain age or sex details. The database includes the date of commencement of redirection, but this may not necessarily be the date of migration.
	Submission of a change of address notice depends on knowing a destination address, and people moving to a new location may first have mail redirected to a temporary address, e.g. the address of a friend or family member before they organise permanent accommodation in their new location.
Geographic level	Suitable:
	Postcode or CD level data allow for sufficient geographic information.
Timeliness and periodicity	Suitable.
Historical availability	Suitable.
Consistency	Suitable.
Electronic capture	Suitable:
	The data are available in some electronic format.
(a) Refer to Table 1

Table 5 Assessment against Evaluation Criteria(a), School enrolment data
Criteria	Assessment
Population and coverage	Unsuitable:
	NSSC school enrolment data cover all enrolled students in Australia, however consistent coverage between states and territories is only available for students aged 6 to 14 years.
Data content	Unsuitable:
	Data are only available in aggregated form rather than at the individual record level.
Geographic level	Unsuitable:
	Although NSSC data are at the suitable state level, they are only available for the school, not the student.
Timeliness and periodicity	Unsuitable: Data are available seven months after the reference quarter.
	Data are only available annually meaning they are unsuitable for quarterly estimates.
Historical availability	Suitable: Historical data are available in aggregate form.
Consistency	Suitable.
Electronic capture	Suitable:
	Data are available electronically in spreadsheet form for government schools or as a CSV file for non-government schools.
(a) Refer to Table 1

Table 6 Assessment against Evaluation Criteria(a), Driver licence data
Criteria	Assessment
Population and coverage	Unsuitable:
	The NEVDIS population is all licensed drivers in Australia except for those in Tasmania. The minimum age at which a licence may be obtained varies across Australia. Not all usual residents of Australia have licences.
Data content	Unsuitable:
	NEVDIS does not contain the address of origin of people who have changed address.
Geographic level	Suitable:
	Postcode level data allow for sufficient geographic information.
Timeliness and periodicity	Suitable.
Historical availability	Unsuitable:
	No historical data are available. If the data source was used, the ABS would have to request and store data as at each point of time required to compile a time series for future use, e.g. for evaluation in 2011.
Consistency	Suitability note yet determined.
Electronic capture	Suitable:
	The data could be captured in some electronic format.
(a) Refer to Table 1

• is 18 years of age or over (17 year olds may enrol but are not eligible to vote until they turn 18), and
• is an Australian citizen, or was a British subject on a Commonwealth electoral roll as at 25 January 1984, and
• has lived for at least one month at their current address (or within the electoral division).

Table 7 Assessment against Evaluation Criteria(a), Australian electoral roll data
Criteria	Assessment
Population and coverage	Suitability not yet determined.
	The Australian electoral roll is intended to include all people who are eligible to enrol to vote in Australian elections. However, the extent of coverage of this population has yet to be determined by the ABS.
	The extent to which interstate migration is promptly reflected in the electoral roll is another potential limitation. This may be a problem if significant numbers of young adults or people who move wait until just before elections to update their details or enrol for the first time.
Data content	Suitable:
	All the required data items are on the electoral roll.
Geographic level	Suitable:
	Addresses are coded to census Collection Districts, which are useful for estimates of interstate migration.
Timeliness and periodicity	Suitable:
	The ABS expects that timeliness will be acceptable and data are available quarterly.
Historical availability	Unsuitable.
Consistency	Suitability not yet determined.
	Consistency of data items is yet to be determined, in discussion with the AEC.
Electronic capture	Suitable:
	The data are available in some electronic format.
(a) Refer to Table 1

Table 8 Assessment against Evaluation Criteria(a), Electricity connections data
Criteria	Assessment
Population and coverage	Unsuitable:
	The MSATS population is all electricity connection points that are of relevance to the National Electricity Market. It is not possible to distinguish between dwellings and businesses, and the database does not cover all dwellings in Australia.
Data content	Unsuitable:
	The dataset does not contain any of the data items required.
Geographic level	Suitable:
	Postcode is included in the address information for those connection points that are on the database.
Timeliness and periodicity	Suitable:
	The data could be obtained promptly each quarter.
Historical availability	Suitable:
	Historical data are available, for some states, back to January 2002.
Consistency	Suitable:
	Data items have been relatively consistent since the introduction of the MSATS system in January 2002. However different jurisdictions have different definitions of 'small' consumption - the category that includes dwellings and small businesses.
Electronic capture	Suitable:
	The data are available in electronic format.
(a) Refer to Table 1

• Financial institutions data;
• Social security data; and
• Other administrative data.

Table 9 Summary of all assessments(a)
Data Source	Population and coverage	Data content	Geographic level	Timeliness and periodicity	Historical availability	Consistency	Electronic capture
Medicare data	Y	Y	Y	Y	Y	Y	Y
Taxation data	N	N	Y	N	Y	Y	Y
Australia Post data	N	N	Y	Y	Y	Y	Y
School enrolment data	N	N	N	N	Y	Y	Y
Driver licence data	N	N	Y	Y	N	nya	Y
Electoral roll data	nya	Y	Y	Y	Y	nya	Y
Electricity Connections	N	N	Y	Y	Y	Y	Y
nya not yet available
(a) Refer to Table 1 for explanation of criteria.