Table 1 Key trial measures

Working memory (population screen)

Children with low working memory will be defined as those scoring < 25^th percentile on both the backward digit recall and the spatial span tasks from the Automated Working Memory Assessment (AWMA) [27].

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Achievement (primary outcome)

Wide Range Achievement Test (WRAT 4) [29] is a validated measure of child academic achievement. It yields standard (mean 100, SD 15) reading composite (word reading and sentence comprehension subtests) and maths computation scores. The WRAT will determine if early working memory benefits translate into subsequent learning. Gains at 12 months not sustained at 24 months would indicate that repeated bursts of working memory training may be helpful.

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Working memory

Automated Working Memory Assessment (AWMA) is standardised for ages 4-22 years, the AWMA is a PC-based, valid and reliable working memory assessment tool that yields composite and subtest scores (mean 100, SD 15) [27]. We will administer the following subtests: digit recall, listening recall, dot matrix, spatial span and backward digit recall (assessing verbal, visuo-spatial and central executive components of working memory). This will show whether short-term working memory gains are made and sustained over time.

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Intelligence Quotient

Wechsler Abbreviated Scales of Intelligence (WASI) [35] is a brief measure of intellectual ability is standardised for ages 6 to 89. Its 4 subscales yield verbal, non-verbal and composite scores (mean 100, SD 15) that correlate strongly with full scale WISC-III scores, and will allow us to explore differential benefits of the program by underlying cognition.

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Health-related quality of life

Peds-QL™4.0 [36]. This 23-item measure for 2-18 year olds provides Total, Physical and Psychosocial scores and is widely used as a proxy for child health-related quality of life.

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The PedsQL - SF15, is a15-item validated child self-report measure for children aged 5 to 7 years yielding a score with a possible range 0-100 [37].

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Quality adjusted life years

Child Health Utility 9D (CHU-9D)[38] is a self-report health-related quality of life questionnaire is validated for children aged 7 to 11, and will be used at the 12 and 24 follow-up to calculate child-reported quality adjusted life years (QALYs) for use in cost-consequences analysis.

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Behaviour

Strengths and Difficulties Questionnaire Parent Report English (Australian) [39]. Widely used, well-validated 25-item questionnaire probing behaviour in 4-16 year olds; yields Prosocial and Total Problem scores as well as emotional, conduct, hyperactivity, and peer subscales.

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SDQ teacher version, for a multi-informant perspective on the program's mental health impacts.

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Academic

National Assessment Program - Literacy and Numeracy (NAPLAN)[40] is an annually administered test for all students in Australian in Years 3, 5, 7 and 9. The assessment consists of four domains of reading, writing, language conventions (spelling, grammar and punctuation) and numeracy.

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Health service utilisation

Medicare data will be accessed from Medicare Australia, which is an Australian Government agency delivering a range of payments and services Australian citizens. Medicare enables Australians have access to free or low-cost medical, optometric and hospital care through a universal health service. Medicare tracks data on health service utilisation from public and private health services [41].

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