1. Introduction

The process of human development provides abundant avenues for interventions aimed at promoting healthy development. We focus our chapter on interventions designed to augment human capital and promote positive behavior, particularly for individuals raised in economically disadvantaged families. Human capital consists of skills acquired in both formal and informal ways that have value either in the labor market (Becker, 1975) or at home (Michael, 1972; 1982). Formal schooling is the most familiär and studied form of human capital. Since it produces both pecuniary rewards in the labor market as well as other important competencies, human capital is one of most important components of healthy development.

Completed schooling is a strong predictor of successful adult outcomes such as longevity, career attainments, and avoiding crime (Fuchs, 1983), as well as such two-generation outcomes as successful parenting (Hoff- Ginsberg &Tardiff, 1995). Nevertheless, researchers have long worried about the potentially spurious nature of these associations. Are they truly the result of the schooling, or do they instead reflect the greater ability or motivation that leads some to complete more schooling? The most sophisticated studies strongly suggest causal impacts of schooling on earnings as well as other positive outcomes, with the apparent social rate of return to investing in additional years of schooling averaging around 10% (Card, 1999). Roughly speaking, this means that investing $10 in interventions that successfully promote the attainment of an additional year of schooling (a difficult task - see below) produces a $ 1 annual increment to participants’ earnings. As we shall see in our review below, few alternative ways of spending $ 10 are likely to yield such a return.

The scope of human capital interventions we consider is quite broad, including those in early and middle childhood, adolescence, as well as early adulthood. We consider intervention programs that target individuals directly as well as programs targeting parents and family environments.

We begin in Section 2 with a review of the economic and developmental logic of interventions. Drawing from both developmental and economic theory, we develop expectations regardingthe “profitability” of intervention programs designed to promote human capital development at different points in life. Economic logic generally supports the view that interventions early in life are likely to be the most profitable, while developmental logic provides a similar set of predictions about the efficacy of interventions at different points in the life course.