The LSAC is funded by the Commonwealth Department of Social Services (DSS). The study was designed by a multidisciplinary team of leading researchers, in
64 collaboration with key stakeholders and policy bodies. LSAC is currently managed by the Australian Institute of Family Studies (AIFS) in partnership with the Australian Bureau of Statistics (ABS; Edwards, 2012). The overarching research questions guiding the LSAC study are: What are the childhood experiences and conditions that impact on child, adolescent and adult outcomes and on trajectories of development? What are the mechanisms underlying linkages and interactions and how do these change over time? What factors and processes protect children from events or contexts that increase the risk of poor outcomes? (Australian Government Department of Families, Housing, Communities, and Indigenous Affairs, 2009).
The LSAC uses a cross sequential research design. Two cohorts of children are being tracked from 2004, with data collection occurring biennially. A total of eight waves of data collection are currently funded. At Wave 1, the B Cohort (Birth or Infant Cohort) were aged less than one year and the K Cohort (Kindergarten Cohort) were aged 4 to 5 years old. Wave 2 occurred in 2006, Wave 3 occurred in 2008 and Wave 4 data was collected in 2010. This study uses data from the first four waves of the B Cohort as released in 2011 in the first release of the Wave 4 dataset.
The first LSAC technical paper provides a detailed description of the sampling design (Soloff, Lawrence, & Johnstone, 2005). The sampling unit for LSAC is the Study Child, with children selected through use of the Medicare Australia database, considered the most comprehensive database of Australia’s child population. A two- stage clustered design was employed. First, 311 postcodes were randomly selected. In the second stage, children were randomly selected from these postcodes resulting in 5107 infants (B Cohort) and 4983 children aged 4-5 years (K Cohort) being selected for the study. A process ofstratification was used to ensure that the numbers of children selected were roughly proportionateto the total numbers of children within each state/territory, and within the capital city statisticaldistricts and the rest of each state
(Soloff et al., 2005). The cohorts have been found to be largely representative of the Australian population (Gray & Smart, 2009). Appendix C provides a table detailing some of the socio-demographic characteristics of the B Cohort and comparing these with population levels of the same characteristics. Where particular groups were under or over represented, weighting of the data is typically used to ensure that the dataset represents as closely as possible, the larger Australian population from which it has
65 been drawn, and to also account for any attrition between waves (Daraganova &
Sipthorp, 2011).
Once selected from the Medicare database, families were contacted with an initial “invitation to participate” package from the AIFS. Families who chose not to ‘opt out’ were then contacted by I-view (subcontracted social and market research company) to arrange an interview time. From Wave 2, the ABS took over responsibility for data collection. Informants used at each wave were Parent 1 (the person who knows the Study Child best), Parent 2, the Study Child him/herself, Parent Living Elsewhere (from Wave 2 on), and teachers and child care workers. Data for each Study Child from relevant national databases were also linked where available. These included the National Childcare Accreditation Council, Medicare Australia, the ABS, the National Assessment Program – Literacy and Numeracy (NAPLAN), and the Australian Early Development Index (AEDI).
The LSAC measures were designed to collect information on multiple areas of child development, health and wellbeing, and the context in which children are raised, particularly their family, child care, school and neighbourhood experiences (Gray & Smart, 2009). The main data collection instruments at each wave for the B Cohort were face to face interviews with Parent 1; a self-complete parent questionnaire (Parent 1 and Parent 2); time use diary; questionnaires for child care workers, teachers and Parents Living Elsewhere; and direct assessments of children’s physical measures. Additionally for the B Cohort, the Who am I (WAI) test for school readiness was conducted at Wave 3, the Peabody Picture Vocabulary Test (PPVT) in Waves 3 and 4, the Matrix
Reasoning Test in Wave 4 and a child self-report measure (conducted by interview) was also implemented in Wave 4. Between-wave data collection was also undertaken
(Waves 1.5, 2.5 and 3.5) in order to maintain contact with each family and gather further information. These consisted of brief questionnaires examining parent and child health status, general development, children’s use of care and schooling and general family circumstances (Daraganova & Sipthorp, 2011).
Data collected at four time points from a selection of families participating in the Birth Cohort of 5107 children is used to address the research questions in the current project. Wave 1 of data was collected during infancy, Wave 2 at age 2-3 years, Wave 3 at age 4-5 years and Wave 4 at 6-7 years. This enables the construct of self-regulation to
66 be examined over the crucial developmental period of birth to age 5, with its
relationship to outcomes as measured at age 6 to 7 years examined. A range of
measurement instruments that conceptually, theoretically and empirically relate to self- regulation are used to address the research questions. Relevant aspects of parenting including maternal mental health and concepts of positive and negative parenting are also used. All measures are described in detail in Section 3.5. The following section describes the sample selection procedure and the characteristics of the participants in the current program of research.