Table 3.

Child outcome measures to be used in the study

Construct	Components	Measure	Baseline	8 weeks follow-up	12 months follow-up
Primary outcomes
Executive function (factor score derived from latent variable modelling estimates—continuous)	Working memory Inhibitory control Attentional shifting	Three short iPad tasks from the Early Years Toolbox39: Mr Ant (visual-spatial working memory): participants remember the spatial locations of ‘stickers’ placed on a cartoon ant and identify these locations after a brief retention interval; Go/No-Go (inhibition): participants respond to ‘go’ trials (catch fish) and withhold on ‘no-go’ trials (avoid sharks). Card-Sorting (shifting): participants sort cards by one sorting dimension first (eg, colour) before switching to sorting by a second dimension (eg, shape).	◆	◆
Self-regulation (factor score derived from exploratory factor analysis of components—continuous)	Behavioural regulation	Head Toes Knees Shoulders Task40: a game whereby children do the opposite of what the researcher says (eg, touch toes when asked to touch their head). A measure of inhibitory control (a child must inhibit the dominant response), working memory (a child must remember the rules of the task) and attention focusing (must focus attention to the directions being presented).	◆	◆
		Child Self-Regulation and Behaviour Questionnaire (CSBQ), Behavioural Self-Regulation subscale. From the Early Years Toolbox39: five items, each on a scale from 1 (not true) to 5 (certainly true).	●	●
	Emotional regulation	CSBQ Emotional Self-Regulation subscale. From the Early Years Toolbox39: six items, each on a scale from 1 (not true) to 5 (certainly true).	●	●
	Cognitive/attentional regulation	CSBQ Cognitive Self-Regulation subscale. From the Early Years Toolbox39: five items, each on a scale from 1 (not true) to 5 (certainly true).	●	●
	Classroom self-regulation	Child Behaviour Rating Scale.41 Teacher-report measure of self-regulation behaviours within the classroom. 10 items rated on a Likert scale from 1 (never) to 5 (always).	●	●
Secondary outcomes
School readiness (single raw score—continuous).		Bracken School Readiness Assessment—Third Edition,42 comprises six subtests (colours, letters, numbers/counting, sizes, comparisons and shapes), assesses knowledge of concepts traditionally taught in preparation for formal education.	◆	◆
Visual-motor integration (single raw score—continuous).		Design Copy task from the Early Screening Inventory.43 A visual-motor task requiring children to use a pencil to copy geometric shapes pictured on cards such as a square or circle.	◆	◆
Academic and developmental competence (composite score—continuous)		Eight items from LSAC comparing how competent child is in various academic and developmental areas, rated on a 5-point scale from much less competent to much more competent.
Behaviour problems (total score—continuous)		Strengths and Difficulties Questionnaire44: 25-item validated measure assessing child’s socioemotional behaviour, including five scales: hyperactivity/inattention, conduct problems, emotional symptoms, peer relationship problems, and prosocial behaviour.
School transition (dichotomised to difficult/average or with ease—binary)		Single item from LSAC comparing how study child has transitioned to school compared with peers. 5-point scale from with much more difficulty, to with much more ease than other children.

◆=direct assessment; ●=preschool educator report; ✹=parent report; =school teacher report.

LSAC, Longitudinal Study of Australian Children.