Overview of the HILDA Survey

The HILDA Survey is a broad social and economic survey, with particular attention paid to family and household formation, income and work. As the HILDA Survey has a longitudinal design, most questions are repeated each year. Nevertheless, within each survey wave, scope exists for asking questions on topics that will not be covered every year. The main additional topics to date are as follows:

• Wave 1 – Family background and personal history variables (subsequently included in every New Person Questionnaire);
• Wave 2 – Household wealth;
• Wave 3 – Retirement and plans for retirement;
• Wave 4 – Private health insurance, and youth.
• Wave 5 – Fertility and Partnering, Personality, Household Expenditure, Intentions and Plans.

The HILDA Sample and Following Rules: A Summary

The HILDA Survey began with a large national probability sample of Australian households occupying private dwellings. All members of the households providing at least one interview in wave 1 form the basis of the panel to be pursued in each subsequent wave. The sample has been gradually extended to include any new household members resulting from changes in the composition of the original households.

Continuing Sample Members (CSMs) are defined to include all members of wave 1 households. Any children subsequently born to or adopted by CSMs are also classified as CSMs. Further, all new entrants to a household who have a child with a CSM are converted to CSM status. CSMs remain in the sample indefinitely. All other people who share a household with a CSM in wave 2 or later are considered Temporary Sample Members (TSMs). TSMs are followed for as long as they share a household with a CSM. The variable hhsm on the masterfile identifies TSMs while the CSMs are split into two groups: OSMs (original sample members from wave 1) and OPMs (other permanent sample members, ie ‘new’ CSMs).

Figure 1 shows an example of how the sample evolved across the first three waves. In wave 1, the sample consisted of 19,914 people. A further 442 births and 54 parents of newborns who were not originally CSMs have been added to the sample in waves 2 and 3. A total of 177 deaths have been identified across the two follow-up waves and 256 people have moved overseas, though 24 returned after being away for one wave. Of the TSMs joining the sample in wave 2, a third had moved out by wave 3.

Figure 1: The Evolution of the HILDA Survey Sample

Questionnaires

In wave 1, the HILDA survey comprised four different instruments. These were:

• the Household Form (HF);
• the Household Questionnaire (HQ);
• the Person Questionnaire (PQ); and
• the Self–Completion Questionnaire (SCQ).

In subsequent waves, the PQ was replaced with two instruments:

• the Continuing Person Questionnaire (CPQ), for people who have been interviewed in a previous wave, and
• the New Person Questionnaire (NPQ), for people who have never been interviewed before (which collects family background and personal history information).

Appendix 1a provides a guide to topics covered in the HILDA Survey across the first five waves. Appendix 1b provides a list of sources used in constructing the questions.

Household Form

The HF is designed to record basic information about the composition of the household immediately after making contact. The HF is the ‘master document’ used by interviewers to decide who to interview, how to treat joiners and leavers of the household, and to record call information and non-interview reasons. The date the HF is completed is provided in _hhcomps.

Household Questionnaire

The HQ collects information about the household rather than about individual household members per se, and is only administered to one member of the household. In practice, however, interviewers are encouraged to be flexible. If more than one household member wishes to be present at the interview this is perfectly acceptable. Further, interviewers are given the flexibility to deliver part of this interview to one household member and part to another. Indeed, this was often required, with questions on childcare needing to be asked of the primary care giver. The date the HQ is completed is provided in _hhqivw.

The HQ mainly covers childcare arrangements, housing, household spending (until wave 5) and, in waves 2 and 6, household wealth.

Person Questionnaires

The CPQ is administered to every member of the household aged 15 years and over who has previously completed a person questionnaire. The NPQ is administered to every member of the household aged 15 years and over who has not previously completed a person questionnaire. Parental consent is sought before interviewing persons aged under 18 years. The date the PQ is completed is provided in _hhidate.

The sections of the person questionnaires are shown in Table 1 together with the letter used to identify the section. These will help you locate questions on the questionnaires (for example, if you wanted to find questions on education, look in section C of the wave 1 Person Questionnaire and section A of the Continuing Person Questionnaire and New Person Questionnaire from wave 2 onwards).

The PQ in Wave 1 is distinctive from that used in the later waves by collecting biographical data that only needs to be asked once. These questions are spread throughout the survey and include questions about country of birth and language, family background, educational attainment, employment history, and marital history. In addition, at later waves further biographical information about visa category for immigrants (wave 4) and parents' education (wave 5) was collected.

The NPQ differs from the CPQ in the inclusion of these additional biographical history questions.

Table 1: Sections of the Person Questionnaires

Self–Completion Questionnaire

Finally, all persons completing a person questionnaire are asked to complete a Self–Completion Questionnaire which the interviewer collects at a later date, or failing that, is returned by mail. This questionnaire comprises mainly attitudinal questions, many of which cover topics which respondents may feel slightly uncomfortable answering in a face–to–face interview. The date that the SCQ is completed is not collected.

Table 2 shows the sections of the SCQ together with the letter used to identify the section.

Table 2: Sections of the Self–Completion Questionnaire