Education and Work, Australia methodology

Two types of error are possible in estimates based on a sample survey: 

• non-sampling error    
• sampling error

Non-sampling error is caused by factors other than those related to sample selection. It is any factor that results in the data values not accurately reflecting the true value of the population.

It can occur at any stage throughout the survey process. Examples include:

• selected people that do not respond (e.g. refusals, non-contact)
• questions being misunderstood 
• responses being incorrectly recorded 
• errors in coding or processing the survey data

Sampling error is the expected difference that can occur between the published estimates and the value that would have been produced if the whole population had been surveyed. Sampling error is the result of random variation and can be estimated using measures of variance in the data.

One measure of sampling error is the standard error (SE). There are about two chances in three that an estimate will differ by less than one SE from the figure that would have been obtained if the whole population had been included. There are about 19 chances in 20 that an estimate will differ by less than two SEs.

The relative standard error (RSE) is a useful measure of sampling error. It is the SE expressed as a percentage of the estimate:

\(\LARGE R S E \%=\left(\frac{S E}{e s t i m a t e}\right) \times 100\)

Only estimates with RSEs less than 25% are considered reliable for most purposes. Estimates with larger RSEs, between 25% and less than 50% have been included in the publication, but are flagged to indicate they are subject to high SEs. These should be used with caution. Estimates with RSEs of 50% or more have also been flagged and are considered unreliable for most purposes. RSEs for these estimates are not published.

Another measure of sampling error is the Margin of Error (MOE). This describes the distance from the population value that the sample estimate is likely to be within and is particularly useful to understand the accuracy of proportion estimates.

The MOE is specified at a given level of confidence. Confidence levels typically used are 90%, 95% and 99%. For example, at the 95% confidence level, the MOE indicates that there are about 19 chances in 20 that the estimate will differ by less than the specified MOE from the population value (the figure obtained if the whole population had been enumerated). The 95% MOE is calculated as 1.96 multiplied by the SE:

\(\LARGE MOE=SE \times 1.96\)

The RSE can also be used to directly calculate a 95% MOE by:

\(\LARGE \operatorname{MOE}(y) \approx \frac{R S E(y) \times y}{100} \times 1.96\)

The MOEs in this publication are calculated at the 95% confidence level. This can easily be converted to a 90% confidence level by multiplying the MOE by:

\(\LARGE \frac{1.645}{1.96}\)

or to a 99% confidence level by multiplying the MOE by:

\(\LARGE \frac{2.576}{1.96}\)

Depending on how the estimate is to be used, a MOE of greater than 10% may be considered too large to inform decisions. For example, a proportion of 15% with a MOE of plus or minus 11% would mean the estimate could be anything from 4% to 26%. It is important to consider this range when using the estimates to make assertions about the population.

A confidence interval expresses the sampling error as a range in which the population value is expected to lie at a given level of confidence. A confidence interval is calculated by taking the estimate plus or minus the MOE of that estimate. In other terms, the 95% confidence interval is the estimate +/- the MOE.

The datacubes report the relative standard error (RSE) for estimates of counts ('000) and the margin of error (MOE) for estimates of proportions (%)(available in the Data downloads section of the main publication).

Time series tables include both RSE of proportion and MOE of proportion. For years prior to 2018, MOE of proportion has been calculated using rounded figures and the result may have slightly less precision than the MOE of proportion calculated for years after 2017.

In the first datacube (Tables 1-20: Education and Work), estimates of proportions with a MOE greater than 10% are annotated to indicate they are subject to high sample variability and particular consideration should be given to the MOE when using these estimates. In addition, estimates with a corresponding standard 95% confidence interval that includes 0% or 100% are annotated to indicate they are usually considered unreliable for most purposes.

Proportions or percentages formed from the ratio of two count estimates are also subject to sampling errors. The size of the error depends on the accuracy of both the numerator and the denominator. A formula to approximate the RSE of a proportion is given below. This formula is only valid when the numerator (x) is a subset of the denominator (y):

\(\LARGE RSE\left( {\frac{x}{y}} \right) \approx \sqrt{[R S E(x)]^{2}-[R S E(y)]^{2}} \)

When calculating measures of error, it may be useful to convert RSE or MOE to SE. This allows the use of standard formulas involving the SE. The SE can be obtained from RSE or MOE using the following formulas:

\(\LARGE SE = \frac{{RSE\% \times estimate}}{{100}}\)

\(\LARGE SE = \frac{{MOE}}{{1.96}}\)

The difference between two survey estimates (counts or percentages) can also be calculated from published estimates. Such an estimate is also subject to sampling error. The sampling error of the difference between two estimates depends on their SEs and the relationship (correlation) between them. An approximate SE of the difference between two estimates (x - y) may be calculated by the following formula:

\(\LARGE S E(x-y) \approx \sqrt{[S E(x)]^{2}+[S E(y)]^{2}}\)

While this formula will only be exact for differences between separate and uncorrelated characteristics or sub populations, it provides a good approximation for the differences likely to be of interest in this publication. 

When comparing estimates between surveys or between populations within a survey, it is useful to determine whether apparent differences are 'real' differences or simply the product of differences between the survey samples. 

One way to examine this is to determine whether the difference between the estimates is statistically significant. This is done by calculating the standard error of the difference between two estimates (x and y) and using that to calculate the test statistic using the formula below:

\( \LARGE \frac{|x-y|}{S E(x-y)}\ \)

where

 \(\LARGE S E(y)\approx\frac{R S E(y) \times y}{100}\)

If the value of the statistic is greater than 1.96, we can say there is good evidence of a statistically significant difference at 95% confidence levels between the two populations with respect to that characteristic. Otherwise, it cannot be stated with confidence that there is a real difference between the populations.

An apprentice is a person who has entered into a legal contract (called a training agreement or contract of training) with an employer, to serve a period of training for the purpose of attaining tradesperson status in a recognised trade. In this survey, persons who are apprentices and trainees are identified by their answer to a question specifically pertaining to a contract under the Australian Apprenticeships scheme. Students undertaking school based apprenticeships are not included.  

Comprises the balance of each state/territory not included in Capital City. See Australian Statistical Geography Standard (ASGS): Volume 1 - Main Structure and Greater Capital City Statistical Areas, July 2016.

Refers to Greater Capital City Statistical Areas (GCCSA) as defined by the ASGS. The GCCSAs represent the socio-economic extent of each of the eight State and Territory capital cities. The whole of the Australian Capital Territory (ACT) is included in the GCCSA.

Survey responses are coded to Certificate not further defined (n.f.d.) when there is not enough information to code them to Certificate I, II, III or IV in the Australian Standard Classification of Education (ASCED), 2001 Level of education classification. 

A person having 'completed' a qualification means they have successfully passed all of the requirements for the qualification and excludes people who have stopped studying without gaining the qualification.  

Country of birth has been classified according to the Standard Australian Classification of Countries (SACC), Second Edition. 'Born in Australia' refers to all persons born in Australia or any of its external territories. 'Born overseas' refers to all persons not 'born in Australia', including those born at sea and persons whose country of birth is unknown.  

Enrolled in a course of formal study for a certificate, diploma, degree or any other educational qualification, in May of the survey year. 

Persons aged less than 15 years who have a parent/guardian in the household.

Any institution whose primary role is education. Included are schools, higher education establishments, colleges of technical and further education and public and private colleges.

Persons who, during the reference week: 

• worked for one hour or more for pay, profit, commission or payment in kind in a job or business, or on a farm (comprising employees, employers and own account workers); or 
• worked for one hour or more without pay in a family business or on a farm (i.e. contributing family workers); or 
• were employees who had a job but were not at work and were: 
  • away from work for less than four weeks up to the end of the reference week; or    
  • away from work for more than four weeks up to the end of the reference week and received pay for some or all of the four week period to the end of the reference week; or 
  • away from work as a standard work or shift arrangement; or 
  • on strike or locked out; or 
  • on workers' compensation and expected to return to their job; or
• were employers or own account workers who had a job, business or farm, but were not at work.
   

Employed persons who usually worked 35 hours or more a week (in all jobs) and those who, although usually working less than 35 hours a week, worked 35 hours or more during the reference week.

Employed persons who usually worked less than 35 hours a week (in all jobs) and either did so during the reference week, or were not at work in the reference week.

The term engagement is used when assessing a persons level of participation in employment and education. People can be Fully engaged, Partially engaged, or Not engaged. For more information, see the 'Key education concepts' section.

Refers to persons registered for a course of formal study in the particular reference period (e.g. survey month, or previous calendar year). This includes online or distance education and excludes any course of study that doesn't result in a formal educational qualification.

Includes persons enrolled in a course of study that is considered full-time by their institution.  

Includes persons enrolled in a course of study that is not considered full-time by their institution. All apprentices and trainees are considered to be enrolled in part-time study.  

Field not determined includes inadequately described responses or where no responses were given. 

The subject matter of the educational activity for the highest achievement a person has attained in any area of formal study.

Refers to the occupation of an apprentice or trainee and is classified according to the Australian and New Zealand Standard Classification of Occupations (ANZSCO), 2013, Version 1.2.

Any study being undertaken that will lead to a recognised qualification, issued by a relevant approved body, in recognition that a person has achieved learning outcomes or competencies relevant to identified individual, professional, industry or community needs. This includes study for a school qualification. In this survey, if the respondent was still attending school their level of study was recorded as their current year of schooling. If the respondent had left school and was enrolled in formal study they were asked the level of the qualification. 

People who were employed full-time and/or in full-time study, or employed part-time combined with part-time study.

An Australian institution providing higher education courses, e.g. universities; colleges of advanced education; institutes of advanced education; institutes of higher education; institutes of tertiary education; agricultural colleges; and some institutes of technology, and the equivalent institutions overseas.

Industry data is classified according to the Australian and New Zealand Standard Industrial Classification (ANZSIC), 2006.

Level of highest educational attainment identifies the highest achievement a person has attained in any area of formal study. It is not a measurement of the relative importance of different fields of study, but a ranking of qualifications and other educational attainments regardless of the particular area of study or the type of institution in which the study was undertaken. For more information regarding how Level of highest educational attainment is derived see the Decision Table: Level of Highest Educational Attainment in the 'Key Education Concepts' section. It is categorised according to the Australian Standard Classification of Education (ASCED), 2001 Level of education classification. Level of education is also classified according to the International Standard Classification of Education (ISCED), 2011. 

A person's level of highest educational attainment (non-school priority) is their highest non-school qualification where they have completed one. For persons who have not completed a non-school qualification their level of highest educational attainment (non-school priority) is the highest year of school they have completed. It is categorised according to the Australian Standard Classification of Education (ASCED), 2001 Level of education classification.

A person's level of highest non-school qualification is the highest qualification a person has attained in any area of formal study other than school study. It is categorised according to the Australian Standard Classification of Education (ASCED), 2001 Level of education classification.

Level not determined includes inadequately described responses or where no responses were given.

The main subject matter of the study undertaken by a person in completing an educational activity. Where a qualification covered multiple fields (e.g. a double degree) the 'main' field is the one considered most important. It is categorised according to the Australian Standard Classification of Education (ASCED), 2001 Field of education classification. Main field of education is also classified according to the International Standard Classification of Education (ISCED), 2011.

Non-school qualifications are awarded for educational attainments other than those of pre-primary, primary or secondary education. They include qualifications at the Postgraduate Degree level, Master Degree level, Graduate Diploma and Graduate Certificate level, Bachelor Degree level, Advanced Diploma and Diploma level, and Certificates I, II, III and IV levels. School level qualifications obtained through institutions other than primary and secondary schools (such as TAFE) are not included. Non-school qualifications may be attained concurrently with school qualifications.

People who were not employed and not studying.

Persons who were not in the categories ‘employed’ or ‘unemployed’. 

Occupation data is classified according to the Australian and New Zealand Standard Classification of Occupations (ANZSCO), 2013, Version 1.2.

People who were employed part-time and not studying, or in part-time study and not employed.

Formal certification, issued by a relevant approved body, in recognition that a person has achieved an appropriate level of learning outcomes or competencies relevant to identified individual, professional, industry or community needs. Statements of attainment awarded for partial completion of a course of study at a particular level are excluded.

The Australian Statistical Geography Standard (ASGS) was used to define remoteness. The Remoteness Structure is described in detail in the publication Australian Statistical Geography Standard (ASGS): Volume 5 - Remoteness Structure, July 2016.

The week preceding the week in which the interview was conducted.

School-based apprenticeships or traineeships are undertaken part-time while at school and combine paid employment as an apprentice or trainee, vocational training and senior secondary school studies. This is a different population to those people who are undertaking apprenticeships or traineeships through the Australian Apprenticeships scheme which are considered separately. 

People aged 15-24 years who attended school in the previous year, but were not attending school in May of the survey year. Note that these people may have been studying a school year level at a non-school institution (e.g. studying Year 12 at TAFE). In this survey, school leavers are grouped by the highest level of school completed: year 12 or equivalent, and year 11 or below.

School study is participation in primary or secondary level education, regardless of the institution or location where the study is or was undertaken. It therefore includes such study undertaken in a Technical and Further Education (TAFE) or other institution.

In this publication, the ABS has described STEM fields of education according to the definition in the Report on Australia's STEM Workforce by the Office of the Chief Scientist. This includes the Australian Standard Classification of Education (ASCED) fields of education: 

01. Natural and Physical Sciences (including 0101. Mathematical Sciences)
02. Information Technology
03. Engineering and Related Technologies
05. Agriculture, Environment and Related Studies

This publication also compares these fields with the fields 04. Architecture and Building and 06. Health; which are described as STEM-related fields and are sometimes included in broader definitions of STEM.

This is one of four Socio-Economic Indexes for Areas (SEIFAs) compiled by the ABS following each Census of Population and Housing, from various characteristics of persons resident in particular areas. The Index of Relative Socio-Economic Disadvantage summarises attributes such as income, educational attainment, unemployment and occupation skill levels. The index refers to the area (the Statistical Area Level 1) in which a person lives, not to the socio-economic situation of the particular individual. The index ranks areas on a continuum from most disadvantaged to least disadvantaged. A low score on the index (i.e. lowest quintile or decile) indicates a high proportion of relatively disadvantaged people in an area. Such areas include many households with low income, people with no qualifications and many people in low skill occupations. It should be noted that it cannot be concluded that an area with a very high score has a large proportion of relatively advantaged ('well off') people, as there are no variables in the index to indicate this. It can only be concluded that such an area has a relatively low incidence of disadvantage. The indexes used in this publication were those compiled following the 2016 Census. For further information about the indexes, see Census of Population and Housing: Socio-Economic Indexes for Areas (SEIFA), Australia, 2016.

Refers to a Technical and further education institution; a registered training organisation owned and operated by a state government, or public provider of training. In Victoria, TAFE may be interpreted as 'Training and Further Education'. TAFE institutions focus on teaching specific skills for a particular workplace.

A trainee is a person who has entered into a legal contract (called a training agreement or contract of training) with an employer, to serve a period of training in a vocational area (e.g. office administration, information technology, hospitality). In this survey, persons who are apprentices and trainees are identified by their answer to a question specifically pertaining to a contract under the Australian Apprenticeships scheme.

Employed persons aged 15 years and over who want, and are available for, more hours of work than they currently have. They comprise:

• persons employed part-time who want to work more hours and are available to start work with more hours, either in the reference week or in the four weeks subsequent to the survey; or 
• persons employed full-time who worked part-time hours in the reference week for economic reasons (such as being stood down or insufficient work being available). It is assumed that these people wanted to work full-time in the reference week and would have been available to do so.

Persons who were not employed during the reference week, and: 

• had actively looked for full-time or part-time work at any time in the four weeks up to the end of the reference week and were available for work in the reference week; or 
• were waiting to start a new job within four weeks from the end of the reference week and could have started in the reference week if the job had been available then.

VET relates to education and training that aims to equip people with knowledge, skills and/or competences required in particular occupations or, more broadly, on the labour market. VET is a component of apprenticeships or traineeships, including those that are school-based. However, VET can be undertaken without also undertaking an apprenticeship or traineeship.