Given our value system, we would like to argue that any demonstrated benefits of intervention are worth the cost…. Unfortunately, for policymakers benefits must be defined in practical terms, and these are always ones of economic feasibility. Only when gains translate into economic savings is the effectiveness of intervention truly conceded. In an era of tight government budgets, it is impractical to consider active investment programmes for all persons. The real question is how to use the available funds wisely. The best evidence supports the policy prescription: invest in the very young and improve basic learning and socialization skills … efficiency would be enhanced if human capital investment were reallocated to the young. (Heckman, 2000, p. 8) Early childhood education is receiving widespread attention as one of the most effective ways to promote children's educational success. Preschool programs are a centerpiece of many school and social reforms; in 2002 alone, government expenditures totaled $22 billion for programs targeting children from birth to age five (White House, 2003). The main attraction of early childhood programs is their potential for prevention and cost-effectiveness, especially when compared to the well-known limits of remediation and treatment (Durlak, 1997; Heckman, 2000). In child welfare and juvenile justice, for example, most services are provided to treat families and children after problems have occurred rather than to prevent the need for services or to provide early intervention (Cohen, 1998; MacLeod & Nelson, 2000).