Wave 3 data collection
Fieldwork
Wave 3 data collection started in March 2008 and was completed in February 2009. Over this period, interviewers from the ABS interviewed 8,718 families, including 4,386 B cohort families (children aged 4 to 5 years in Wave 3) and 4,332 K cohort families (children aged 8 to 9 years in Wave 3).
Most of the interviews followed the standard procedure of a face-to-face interview in English with the child's primary care giver (usually the mother). The exceptions were:
- Eighty-seven telephone interviews for families living in remote areas. Most of these were in Western Australia and South Australia.
- Ninety-seven interviews conducted in a language other than English. Of these, 58 were interpreted by a family member or friend (of the study family), 31 were interpreted by an ABS interviewer fluent in the relevant language, and eight interviews involved a Translating and Interpreting Service (TIS) interpreter. The most common languages requiring an interpreter were Arabic, Vietnamese and Cantonese.
Children were measured and assessed and their other resident parent and teachers (or carer) completed questionnaires. Children in the K cohort were also interviewed face-to-face. Parents living apart from the child were interviewed by telephone.
The average time spent by interviewers in the home was approximately one and a half hours. This was shorter than the Wave 1 average of two hours but slightly longer than the one and one-quarter hours required for Wave 2. In Wave 3, the average time in the household for the B cohort was 91 minutes, compared with 98 minutes for the K cohort.
Wave 3 response
There were 8,718 interviews with the primary care giver in Wave 3, which represents 86 per cent of the Wave 1 sample and 89 per cent of the available sample in Wave 3 (the available sample excludes families who had permanently withdrawn from the study since Wave 1). Table 1 provides a summary of the sample loss since Wave 1, and shows the number and percentage eligible and who participated at the various main wave data collections.
Two hundred and sixty-eight families who did not participate in Wave 2 took part in the study again in Wave 3. Two-thirds of these families were unable to be contacted in Wave 2 (177 families) and one-quarter refused participation (65 families) in Wave 2. By continuing to take part in the study these families have helped maintain the sample size within LSAC.
| Sample | B cohort | K cohort | Total | ||||||
|---|---|---|---|---|---|---|---|---|---|
| N | Response rate | N | Response rate | N | Response rate | ||||
| % Wave 1 | % Available sample | % Wave 1 | % Available sample | % Wave 1 | % Available sample | ||||
| Wave 1 original | 5,107 | 100.0 | 4,983 | 100.0 | 10,090 | 100.0 | |||
| Wave 2 availablea | 5,047 | 98.8 | 4,913 | 98.6 | 9,960 | 98.7 | |||
| Wave 2 respondingb | 4,606 | 90.2 | 91.2 | 4,464 | 89.6 | 90.9 | 9,070 | 89.9 | 91.1 |
| Wave 3 availablea | 4,971 | 97.3 | 4,829 | 96.9 | 9,800 | 97.1 | |||
| Wave 3 respondingb | 4,386 | 85.9 | 88.2 | 4,332 | 86.9 | 89.7 | 8,718 | 86.4 | 89.0 |
Notes:
(a) Available sample excludes those who opted out of the study prior to the start of the wave. Some additional families also opted out permanently during the fieldwork process.
(b) Responding sample is those who participated in the home visit (or telephone interview for those in remote locations).
A total of 427 families refused to participate in Wave 3--including 257 families who refused to participate in this wave only and 170 who chose to permanently opt out of the study. Of those families who chose not to participate in Wave 3 only, the most common reasons given were: too busy (49 per cent); death or illness (10 per cent); and personal or family problems (14 per cent). Of those families who chose to opt out of the study permanently, approximately 30 per cent stated they were too busy and a further 29 per cent stated they were no longer interested.
Characteristics of non-participating families
Table 2 shows selected Wave 1 characteristics of Wave 3 respondents and non-respondents. Families in which the primary care giver's main language at home was not English, the study child was Indigenous, and the parental income was less than $1,000 per week were less likely to participate in the main study interview in Wave 3. Responding primary care givers were also older on average than non-responding primary care givers. These findings are consistent with patterns of non-response observed in Wave 2. To adjust for this, weights are provided with LSAC data for researchers to use when they are making estimates about the Australian population. These weights ensure the sample used for analysis is still representative of these groups.
| Wave 1 characteristics | B cohort | K cohort | ||
|---|---|---|---|---|
| Responding (%) | Non-responding (%) | Responding (%) | Non-responding (%) | |
| Parent 1 main language spoken at home | ||||
| English | 87.4 | 74.3 | 86.3 | 72.1 |
| Other | 12.6 | 25.7 | 13.7 | 27.9 |
| Study child Indigenous status | ||||
| Indigenous | 3.4 | 11.2 | 2.9a | 9.7 |
| Non-Indigenous | 96.6 | 88.8 | 97.1a | 90.3 |
| Parent 1 | ||||
| Mean age in years (95% CIb) | 31.4 (31.2, 31.5) | 28.9 (28.5, 29.4) | 35.0 (34.8, 35.1) | 33.3 (32.8, 33.8) |
| Parental income | ||||
| <$1,000 | 43.9 | 61.6 | 38.9 | 58.6 |
| >=$1,000 | 56.1 | 38.4 | 61.1 | 41.4 |
| N | 4,386 | 721 | 4,331 | 652 |
Notes:
(a) N is 4,329 because two respondents didn't answer.
(b) 95 per cent CI refers to the 95 per cent confidence intervals around the mean. For example, we can be 95 per cent confident that the mean parental age of B cohort non-respondents lies between 28.5 and 29.4. Parent 1 is the nominated primary care giver who completed the main interview.
Response to other study instruments
The response rate for the other survey instruments (as a percentage of the instruments distributed to families or mailed out) is shown in Table 3.
| Survey instrument | B cohort Wave 3 response rate (%) | K cohort Wave 3 response rate (%) |
|---|---|---|
| Parent 1 | 87 | 88 |
| Parent 2 leave behind form | 71 | 72 |
| Parent living apart from the child | 67 | 67 |
| Time use diary | 68 | 69 |
| Teacher | 83 | 85 |
Notes:
Parent 1 is the nominated primary care giver who completed the main interview.
Parent 2 is a parent other than Parent 1 living with the child.
In Wave 3, a self-complete form was given to the primary care giver. Ideally, this form was completed during the home visit to maximise the response rate; however, some parents were not able to do so and kept it for completion at a later time. This form was completed by 88 per cent of respondents. A form left behind for the child's other resident parent was completed by over 70 per cent of these parents.
In Wave 3 a change in methodology was introduced for parents living apart from but in contact with their child. Where a primary care giver provided contact details, the other parent completed a telephone interview. The response rate from parents living apart from the child was very positive.. Most of the non-response was due to primary care givers not providing contact information or the contact information being inadequate. Of the 856 parents living apart from the child whom interviewers attempted to contact only 53 (6 per cent) refused an interview.
Teacher forms are sent to the school principal to pass to the child's teacher. Over four-fifths of teachers took part in Wave 3.
Final Wave 3 sample characteristics
Table 4 provides a summary of selected characteristics of the LSAC sample compared to Australian population data from the ABS 2006 Census of Population and Housing.
| Characteristics | B Cohort | K Cohort | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Wave 1 | Wave 2 | Wave 3 | Wave 1 | Wave 2 | Wave 3 | |||||||
| LSAC % | ABS % | LSAC % | ABS % | LSAC % | ABS % | LSAC % | ABS % | LSAC % | ABS % | LSAC % | ABS % | |
| Gender(a) | ||||||||||||
| Family type | ||||||||||||
| Siblings | ||||||||||||
| Ethnicity | ||||||||||||
| Work status | ||||||||||||
| Educational Status | ||||||||||||
| State(a) | ||||||||||||
| Region | ||||||||||||
| Male | 51.2 | 51.4 | 51.1 | 51.4 | 51.3 | 51.4 | 50.9 | 51.2 | 51.0 | 51.2 | 51.1 | 51.1 |
| Female | 48.8 | 48.6 | 48.9 | 48.6 | 48.7 | 48.6 | 49.1 | 48.8 | 49.0 | 48.8 | 48.9 | 48.9 |
| Two resident parents/guardians: | 90.7 | 88.3 | 89.0 | 85.1 | 88.9 | 82.5 | 86.0 | 82.5 | 85.2 | 81.0 | 85.6 | 79.8 |
| - both biological | 90.1 | na | 88.0 | na | 85.9 | na | 82.9 | na | 81.3 | na | 78.8 | na |
| - step or blended family | 0.2 | na | 0.8 | na | 2.9 | na | 2.2 | na | 3.5 | na | 6.4 | na |
| - other | 0.4 | na | 0.2 | na | 0.1 | na | 1.0 | na | 0.4 | na | 0.4 | na |
| One resident parent/guardian: | 9.3 | 11.7 | 11.0 | 14.9 | 11.1 | 17.5 | 14.0 | 17.5 | 14.8 | 19.0 | 14.4 | 20.2 |
| - biological | 9.3 | na | 10.9 | na | 11.0 | na | 13.9 | na | 14.7 | na | 14.2 | na |
| - other | 0.1 | na | 0.1 | na | 0.1 | na | 0.1 | na | 0.1 | na | 0.2 | na |
| Only child | 39.5 | 39.4 | 19.3 | 24.4 | 10.4 | 13.4 | 11.5 | 13.4 | 9.1 | 11.0 | 8.2 | 9.8 |
| One sibling | 36.8 | 35.5 | 49.1 | 45.5 | 48.1 | 47.9 | 48.4 | 47.9 | 45.2 | 44.9 | 44.2 | 42.9 |
| Two or more siblings | 23.7 | 25.1 | 31.6 | 30.0 | 41.5 | 38.7 | 40.1 | 38.7 | 45.7 | 44.1 | 47.6 | 47.3 |
| Aboriginal or Torres Strait Islander | 4.5 | 4.3 | 3.9 | 4.3 | 3.4 | 4.5 | 3.8 | 4.5 | 3.4 | 4.5 | 2.9 | 4.4 |
| Parent 1 speaks a language other than English at home | 14.5 | 18.0 | 13.4 | 18.5 | 12.6 | 18.2 | 15.7 | 18.2 | 14.7 | 18.5 | 13.8 | 18.0 |
| Both parents or lone parent work | 47.9 | nc | 56.9 | nc | 63.0 | nc | 55.5 | nc | 65.4 | nc | 72.8 | nc |
| One parent works (in couple family) | 40.8 | nc | 33.8 | nc | 29.7 | nc | 32.8 | nc | 26.1 | nc | 20.7 | nc |
| No parent works | 11.3 | nc | 9.3 | nc | 7.4 | nc | 11.6 | nc | 8.6 | nc | 6.5 | nc |
| Mother completed Year 12 | 66.9 | nc | 69.0 | nc | 69.8 | nc | 58.6 | nc | 60.1 | nc | 61.4 | nc |
| Father completed Year 12 | 58.5 | nc | 59.7 | nc | 60.4 | nc | 52.7 | nc | 53.2 | nc | 54.0 | nc |
| New South Wales | 31.6 | 33.5 | 31.1 | 33.2 | 31.1 | 33.1 | 31.6 | 33.1 | 31.1 | 33.3 | 30.8 | 33.0 |
| Victoria | 24.5 | 24.5 | 24.3 | 24.7 | 24.6 | 24.3 | 25.0 | 24.3 | 24.3 | 24.2 | 24.4 | 24.2 |
| Queensland | 20.6 | 20.3 | 21.4 | 20.3 | 22.0 | 20.5 | 19.8 | 20.5 | 21.4 | 20.4 | 20.8 | 20.5 |
| South Australia | 6.8 | 6.8 | 6.7 | 7.1 | 7.0 | 7.1 | 6.8 | 7.1 | 6.7 | 7.2 | 6.9 | 7.3 |
| Western Australia | 10.4 | 9.8 | 10.6 | 9.8 | 10.3 | 9.8 | 10.2 | 9.8 | 10.6 | 9.8 | 10.2 | 10.0 |
| Tasmania | 2.2 | 2.3 | 2.3 | 2.3 | 2.4 | 2.4 | 2.7 | 2.4 | 2.3 | 2.4 | 3.0 | 2.4 |
| Northern Territory | 1.7 | 1.1 | 1.4 | 1.2 | 1.2 | 1.2 | 1.7 | 1.2 | 1.4 | 1.2 | 1.4 | 1.2 |
| Australian Capital Territory | 2.1 | 1.7 | 2.2 | 1.6 | 2.4 | 1.5 | 2.3 | 1.5 | 2.2 | 1.6 | 2.5 | 1.6 |
| Capital City Statistical Division | 62.5 | 64.9 | 61.9 | 64.4 | 61.8 | 62.8 | 62.1 | 62.8 | 61.6 | 62.1 | 61.4 | 61.4 |
| Balance of state | 37.5 | 35.0 | 38.1 | 35.6 | 38.2 | 37.2 | 37.9 | 37.2 | 38.4 | 37.9 | 38.6 | 38.5 |
| Number of observations | 5,107 | 4,606 | 4,386 | 4,983 | 4,464 | 4,331 | ||||||
Notes: ABS data for characteristics marked with (a) are based on the Estimated Resident Population for children aged 0 years (2004), 2 years (2006) and 4 years (2008) for comparison with the B cohort, and aged 4 years (2004), 6 years (2006), and 8 years (2008) for comparison with the K cohort. For all other characteristics,
ABS data is based on 2006 census counts for families with children aged 0 years (Wave 1, B cohort), 2 years (Wave 2, B cohort), 4 years (Wave 3, B cohort and Wave 1, K cohort), 6 years (Wave 2, K cohort), and 8 years (Wave 3, K cohort).
na=not available; nc=comparable data not available.