Table 3.

Predictors of self-regulation growth in the model

Construct	Data source	Measure
Health & Health Behaviours
Physical health	Parent	Physical Health Summary score from the Pediatric Quality of Life Inventory (PedsQL) [17]. Summed and average score of 8 items each rated on 5-point scale, tapping a child’s level of functioning in daily activities that rely on good physical health. E.g. problems with running. α = .72
Diet quality	Parent	Units of high sugar drinks consumed in the last week
Behavioural sleep problems	Parent	Five items modelled as a latent variable as per prior studies [18]. E.g. child has problems on 4 or more nights a week with waking during the night (yes/no); this child’s sleep is a small/moderate/large problem.
Development
Receptive vocabulary	Assessed	Peabody Picture Vocabulary Test [19] of receptive vocabulary in which children listen to a spoken word and are asked to point to the matching picture given a set of four pictures. Higher scores represent higher receptive vocabulary skills.
Gross motor development	Teacher	On a 4-point scale from ‘much less competent than peers’ to ‘more competent than peers’
Fine motor development	Teacher	On a 4-point scale from ‘much less competent than peers’ to ‘more competent than peers’
Pre-academic skills	Assessed	Who Am I test [20]. Children write their names, copy shapes, write words and numbers; scored according to skill level. α = .89 [21]
Home environment
Maternal parenting anger	Mother	Composite measure (weighted mean score) as per LSAC technical advice [22] using four adapted items from the National Longitudinal Study of Children & Youth [23]. Each item rated on 5-point scale from ‘never or almost never’ to ‘almost always’. E.g. how often are you angry when you punish this child? H = .72.
Paternal parenting anger	Father
Maternal parenting consistency	Mother	Composite measure as per LSAC technical advice [22] using five items from the National Longitudinal Survey of Children and Youth [23]. Each item rates on a 10-point scale from ‘not at all’ to ‘all of the time’. E.g. how often does this child get away with things that you feel should have been punished? H = .80 for father; .82 for mothers.
Paternal parenting consistency	Father
Maternal mental health	Mother	Kessler K6 screening scale [24] of six items (summed and averaged) about respondents’ feelings over the past four-week period. Rates on 5-point scale from ‘all of the time’ to ‘none of the time’. E.g. in the past 4 weeks how often have you felt hopeless? α = .84 for mothers, .82 for fathers.
Paternal mental health	Father
Home learning environment	Parent	Single item book reading; plus latent variable with five indicators of other home learning activities including music, art, and play as used in other LSAC studies [25]. Each rated on 4-point scale of frequency of adult-child engagement  for each activity in the last week from ‘not in the past week’ to ‘6–7 days in the week’.
Financial hardship	Parent	7-item count index ranging from 0 to 7, based on summing Yes = 1, No = 0 responses to 7 items including couldn’t pay bills, gone without meals as used in prior LSAC research [26].
Argumentative parental relationships	Parent	Composite of 5 items (summed and averaged) rated on a 5-point scale from ‘never’ to ‘always’. E.g. my partner and I argue; disagree over child-rearing etc. α = .80
Stressful life events	Parent	13-item count index ranging from 0 to 13 based on summing Yes = 1, No = 0 responses about exposure to adverse life events over the past year including marital breakdown, death of friend, as per prior LSAC research [27].
Education
Teacher-child relationship	Teacher	8-item composite drawn from the Student Teacher Relationship Scale [28] following prior LSAC factor modelling [29]. Each item rated on 5-point scale from ‘definitely does not apply’ to ‘definitely applies’. E.g. share affectionate relationships, easy to be in tune with feelings α = .81
Time use
Extra-curricular sport	Parent	Sum of 3 items indicating participation (yes / no) in extra-curricular swimming, gymnastics, or team sport
Extra-curricular music / dance	Parent	Sum of 2 items indicating participation (yes / no) in extra-curricular music and dance
Weekday TV hours	Parent	Number of hours watching TV on a typical weekday
Weekday computer hours	Parent	Number of hours using a computer on a typical weekday
Physical activity	Parent	Parent-rated child enjoyment of physical activity on a 5-point scale from ‘very much dislikes physical activities’ to ‘very much likes physical activity’
Neighbourhood
Liveability	Parent	Composite (sum) of 8 items each rated on 4-point scale from ‘strongly disagree’ to ‘strongly agree’. E.g. this is a safe neighbourhood, this neighbourhood has good parks. α = .76
Socio-economic index for area (SEIFA)	Australian Bureau of Statistics	Composite of 31 variables (e.g. income, unemployment, occupation and education) computed by the Australian Bureau of Statistics [30].