Abstract : Longitudinal research reveals that well designed and carefully implemented early-in-life intervention programs can produce positive short- and long-term benefits for at-risk children and their families. Benefits include gains in intellectual and academic achievement scores, improvements in educational outcomes, reductions in behavioural problems and delinquency, and improved family wellbeing. Convincing as this research is, not all programs produce benefits to the individual and his/her family; nor may they each produce net savings with respect to the costs of the criminal justice or education systems, or be cost-effective in terms of improved quality of life, feelings of safety, and enhanced wellbeing and happiness.

Economists have applied cost-benefit methodologies to measure the short- and long-term economic impacts of particular early childhood intervention programs. However, most economic analyses of such programs have focused on the governmental perspective (e.g. savings to the criminal justice system) with little emphasis placed on a more holistic, individual-level approach that measures benefits across multiple domains of life. Moreover, policy-makers have had access to a limited set of economic tools to assist them in making well-informed policy choices. This is particularly salient given the multiplicity of criteria that must be taken into account when making judgments that potentially have large effects on individuals and their families.

There are two prominent methodological deficiencies in the developmental prevention literature. The first deficiency is the limited array of methodological tools available to assist when making choices on resource allocation and engaging in a structured decision-making process with respect to alternative policy options for early childhood interventions. The second deficiency is the absence of a rigorous tool for measuring the economic impact of early childhood interventions on salient aspects of non-health related quality of life throughout an individual’s life, such as educational success, cognitive development, and social-emotional development. These aspects of quality of life are the primary focus of early intervention and developmental prevention programs.

In this thesis methods are developed to address both deficiencies. In the first study, a meta-analysis is conducted of the longitudinal research on the impact of early childhood interventions on the adolescent life phase. This study includes a detailed analysis of the psychometric properties of outcome measures relating to individuals’ cognitive, social, and emotional development. Adolescence was selected because of the richness of follow-up data available for this life phase compared to other life phases (e.g. adulthood 28+ years), and because governments invest heavily in policies designed to combat adolescent problems such as delinquency, juvenile crime, drug abuse and conflict at school. A further practical reason for the adolescent focus is the complexity of gathering utility values for all life phases. 

The second study adapts the analytical hierarchy process to develop a method for making complex multi-criteria decisions with respect to policy options for early childhood interventions. This procedure permits analysts to identify common metric outcomes across competing and often disparate programs, such as home visitation to pregnant teenage women and centre-based developmental day care, with the goal of eliciting preferences and relative utility values. Additionally, the second study provides an outline of how relative utility values derived using the analytical hierarchy process approach may be used to identify the economic benefits of developmental prevention programs on non health-related quality of life outcomes in adolescence.

The meta-analysis highlighted the effects that early childhood interventions have on seven outcome domains during adolescence. Results demonstrated that early childhood intervention programs had the largest effect on educational success during adolescence followed  (in order) by social deviance, social participation, cognitive development, criminal justice outcomes, family wellbeing, and social-emotional development. The analysis also revealed that programs that incorporated a structured preschool or centre-based educational component yielded positive effects on the outcome domains educational success and cognitive development throughout the adolescent life phase. Programs with a follow-through component into the early primary school years (e.g. preschool to Grade 3) also displayed strong effects on educational success and cognitive development in adolescence. Additionally, programs whose duration was longer than three years revealed larger sample means than programs that were longer than one year but shorter than three years. Program intensity was also found to be an important moderator of success. In combination, length and intensity of programs were important influences on the domains educational success, cognitive development, and deviancy.

In the second study, a survey of four stakeholder groups (policy people, people working in schools, a community agencies group, and an academic group) provided insights into priority rankings of alternative early childhood intervention programs and relative utility values. It was found that family wellbeing was the highest priority with respect to its perceived contribution to non health-related quality of life during adolescence, with the child’s social-emotional development the second highest priority.

When potential levels of program success were compared (from very high (VH) through H (high) to small (S) or no effect (N)), it was found that the larger the gap between levels (e.g., VH and S), the higher the preference score. Conversely, the smaller the gap between the levels of success (e.g. S and N) the smaller the preference score. Preference scores were not linear, with little discrimination between large effects (e.g. VH with  H).  This finding was consistent across all outcome domains. Respondents did not consider any level of success to be absolutely more important than any other, suggesting, in part, that they believed that some effect was better than no effect.

Study 2 revealed that a structured preschool program was considered the highest priority with respect to contributing to a strong effect on all outcomes during the adolescent years. This was followed in order of priority by family support services, parent education, centre-based childcare/ developmental day care, and home visitation. Using a hypothetical example, Study 2 also showed how relative utility values  may be utilised to reveal the economic benefits (cost-utility) of early-in-life intervention programs on non health-related quality of life outcomes in the adolescent years.

Both studies had limitations that should be able to be overcome in future analyses. For example, it would have been beneficial in the meta-analysis to know how children from culturally and linguistically diverse groups differed in their responses to early-in-life intervention programs, and to have data on the effectiveness of early childhood intervention programs in different geographical locations. With respect to the second study (the analytical hierarchy process), a more detailed hierarchy that incorporated the most relevant indicators associated with the seven outcome domains (e.g. rates of special education, school graduation, or school drop-out) would have provided a more refined set of priority weights (or relative utilities) for adolescent outcomes. Further, incorporating elements such as length and intensity of program, and the use of follow-up, multi-component, or multi-contextual programs into the hierarchy would have been beneficial. These refinements were not possible in this study due to the survey procedures required to identify all the associated pair-wise comparisons, which would have been extremely expensive and time consuming to conduct. Consequently, it is proposed that a series of separate follow-up studies be conducted using this methodology to identify relative .....