Exposure to disadvantage over time is associated with adverse child development outcomes. Developmental outcomes varied with the aspects of disadvantage experienced, highlighting potential targets for more precise policy responses. The findings provide evidence to stimulate advocacy and action to reduce child inequities.

Objectives: Children's additional health and developmental needs are often first identified by teachers when they begin school. This study estimates the Grade 3 literacy and numeracy outcomes of children with teacher-identified additional needs emerging in the first year of school, including the added burden conferred by socioeconomic disadvantage. Methods:Population linked data (n = 42,619) were analysed from the Australian Early Development Census, which include teacher reports on children's health and development at school entry, and the National Assessment Program-Literacy and Numeracy, a direct assessment of reading and numeracy skills at Grade 3. Linear regression analyses were used to estimate associations between emerging needs and learning outcomes, adjusted for sociodemographic characteristics. The combined effect of emerging needs and low maternal education (an indicator of socioeconomic disadvantage) on academic outcomes was examined by estimating the relative excess risk due to interaction (RERI). Results: Emerging health and developmental needs at school entry were associated with lower reading (b = −26.86, 95% CI = −29.19, −24.52) and numeracy (b = −24.39, 95% CI = −26.43, −22.35) outcomes at Grade 3. The combined effect of emerging needs and socioeconomic disadvantage was greater than expected when their individual effects are summed (RERI = 0.38, 95% CI 0.22, 0.55 for reading and RERI = 0.27, 95% CI 0.10, 0.43 for numeracy).Conclusion: In the current study, emerging health and developmental needs identified by teachers at the outset of schooling were associated with poorer literacy and numeracy skills at Grade 3, and family socioeconomic disadvantage appeared to further amplify this effect. Meeting the needs of these children will require timely and coordinated supports across the health and education systems, particularly for those children who are also disadvantaged. K E Y W O R D Sacademic achievement, additional needs, disability, school functioning, special educational needs and disabilities, special health care needs

Children's overall level of composite disadvantage was stable over time, whereas geographic environments, health conditions and risk factors changed over time for some children. Measuring disadvantage as uni-dimensional, at a single time point, is likely to understate the true extent and persistence of disadvantage.