The Confusion, Hubbub and Order Scale (CHAOS) – short form – is a survey tool intended to capture information about home environments. It is widely used in studies of child and adolescent development and psychopathology, particularly twin studies. The original long form of the scale comprised 15 items and was validated in a sample of infants in the 1980s. The short form of the scale was developed in the late 1990s and contains six items, including four from the original scale, and two new items. This short form has not been validated and is the focus of this study. We use five samples (N=10,898) from studies in Australia, the UK, and the USA, to examine the measurement properties of the CHAOS short form. We first compare alternate confirmatory factor models for each group; we next test between-group configural, metric and scalar invariance; finally, we examine predictive validity of the scale in each sample under different conditions. We find evidence that a two-factor configuration of the six items is more appropriate than the commonly used one-factor model. Second, we find measurement non-invariance across groups at the metric invariance step, with items performing differently depending on the sample. By contrast we find longitudinal measurement invariance in two of the three samples with multi-wave data collection on the CHAOS. Finally, we report inconsistent results in tests of predictive validity using family-level socioeconomic status and academic achievement as criterion variables. The results caution the continued use of the short-form CHAOS in its current form and recommend future revisions and development of the scale for use in developmental research.

Decades of educational genetics research have highlighted that differences in academic achievement are partly explained by genetic variation between individuals. Consequently, there is ongoing discussion about whether genetic influences on educationally related traits should be more widely acknowledged in schools and communicated specifically to teachers. Nonetheless, there is little research on how teachers might interpret such information, and how it might alter their perceptions of the students they teach or their teaching practice. In this review, we draw on the mixed blessings model proposed by Haslam and Kvaale, Current Directions in Psychological Science, 2015, 24, 399-404, as a framework for defining both positive and negative repercussions of disseminating the findings of educational genetic research to teachers. We discuss research examining teacher perceptions of student ability and behavior and findings outlining perceptions of psychological disorders when genetic explanations are invoked. We conclude by proposing new directions for research designed to better understand interpretations of genetic information in school contexts.

Attention skills are strong cross-sectional predictors of reading comprehension from childhood through to adolescence. However, less is known about the developmental relations between these two domains across this period. This study examined the codevelopment of reading and attention in a community sample of 614 Australian school students (50% female). Reading and attention were assessed at ages 8, 10, 12, and 14. Results of univariate latent growth models demonstrated, on average, curvilinear trajectories for reading in which rapid growth across younger age spans decelerates as children reach adolescence. By contrast, attention skills remained relatively stable on average. Significant negative correlations were observed between the intercept and slope factors in separate reading (r = -.62) and attention models (r = -.39) suggesting compensatory growth patterns in which poorer performing students in both domains at age 8 have steeper trajectories than their higher performing peers. A comparison of a multivariate latent growth model and an autoregressive latent trajectory model with structured residuals (ALT-SR) examined the interrelatedness of development in reading and attention. Both between-individual and within-individual cross-domain parameters showed reading and attention to be positively related at Grade 3, indicating an association between better attention and higher reading achievement at age 8. However, there was little evidence for interrelated growth across domains in this sample. The results contribute to theories which explain whether and how multiple cognitive domains codevelop over a substantial period of childhood and early adolescence.

A higher proportion of students are privately educated in Australia, compared with many other nations. In this paper, we tested the assumption that private schools offer better quality education than public schools. We examined differences in student achievement on the National Assessment Programme: Literacy and Numeracy (NAPLAN) between public, independent, and catholic schools. Cross-sectional regressions using large samples of students (n = 1583-1810) at Years 3, 5, 7 and 9 showed few sector differences in NAPLAN scores in any domain. No differences were evident after controlling for socioeconomic status and prior NAPLAN achievement. Using longitudinal modelling, we also found no sector differences in the rate of growth for reading and numeracy between Year 3 and Year 9. Results indicate that already higher achieving students are more likely to attend private schools, but private school attendance does not alter academic trajectories, thus undermining conceptions of private schools adding value to student outcomes.

Each year in Australia, all students in Grades 3, 5, 7 and 9 undertake standardized literacy and numeracy assessments. One of the key purposes of this assessment program, the National Assessment Program: Literacy and Numeracy (NAPLAN), is to provide information about students’ attainment and growth in basic skills to schools and educational systems. The work in this thesis therefore applies a developmental perspective to the examination of achievement and growth in these basic skills. Two complementary approaches are used throughout to examine achievement across the span of NAPLAN assessments. First cross-sectional analyses, repeated at each assessed grade, provide insights into predictors of achievement, and how their influence may vary over time. Second, longitudinal methods examine growth trajectories of the reading comprehension and numeracy domains from Grade 3 through to Grade 9. The central aim of the work overall is to further understandings of the variation in achievement both at each assessment point and in trajectories of skills over time.

The first chapter describes the background to the study which provided the data used in Chapters 2 to 4 of the thesis. The Academic Development Study of Australian Twins recruited 2762 Australian twin pairs, and 1465 siblings, and tracked them from Grade 3 through to Grade 9. A range of demographic and behavioural data was collected concurrent to the participants’ completion of NAPLAN tests. Chapters 2, 3 and 4 used data from one randomly selected twin and/or sibling to examine predictors of development in literacy and numeracy.

The second chapter used cross-sectional methods to examine whether delaying the initial school start of students for one year was associated with higher attainment in NAPLAN assessments at each grade. Results of these analyses indicate that while old-for-grade students appear to have a slight advantage over their younger peers in Grade 3, this advantage fades out and is no longer evident in Grades 7 and 9. Furthermore, exploratory analyses examining inattention and hyperactivity suggest that these child-specific behavioural characteristics attenuate the observed early relations between delayed entry and achievement.

The third chapter employed both cross-sectional, and longitudinal methods to examine whether students who attended private schools had systematically higher achievement on NAPLAN tests compared with their peers in public schools. Cross-sectional results at the four grades indicated that once the socioeconomic background of students was controlled, any associations between private school attendance and higher achievement largely disappeared. Further, latent growth curve analyses enabled comparisons of growth for groups of students attending different school sectors at the four NAPLAN grades. Results showed that growth trajectories in reading comprehension and numeracy were no different for those attending public schools, those attending private schools, and those changing from public to private schools as they entered secondary school in Grade 7.

The fourth chapter focused more specifically on the development of reading comprehension, examining how growth in this academic skill is related to developmental change in inattention from age 8 through to 14. This study compared two latent growth modelling approaches: a multivariate latent growth curve model allowing intercepts and slopes of the two domains to correlate, and an autoregressive latent growth model with structured residuals, which separates out between-person relations from within-person growth. Results demonstrated that while reading and inattention were strongly related in Grade 3, relations between the developmental trajectories of these two domains were inconsistent.

The final chapter examined whether Matthew Effects were evident in longitudinal population data sourced from two Australian states, NSW (N= 88,958) and Victoria (N= 65,984). Again, latent growth curve analyses were employed to examine variation in growth trajectories in NAPLAN reading comprehension and numeracy tests at the four grades. Results demonstrated that, rather than Matthew Effects, growth in both domains in both states was characterised by compensatory growth patterns. These patterns suggest that students who start with below average attainment at Grade 3 make more progress in their basic skills attainment over time, compared with their peers who start with above average achievement.

Replicating work from the smaller samples of Chapters 2 to 4 with population-level data provides information about development across the full distribution of achievement, and additional evidence that results in the first four chapters are generalisable to the population

The work presented in this thesis contributes to an understanding of how literacy and numeracy skills develop from middle childhood through to adolescence. Results have the potential to inform future targets for educational policy revision (Chapters 2 and 3), the timing of academic interventions (Chapter 4), and provide baseline information about growth trajectories in reading and numeracy (Chapter 5) that can be useful in evaluating school- or system-level changes to educational practices in Australia.