Through theory, observation, and behavioral study, scientists have determined that select facets of human behavior can be changed over time. Specifically, the effects of malleable risk factors can be reduced, protective factors can be enhanced or developed, and resources can be accessed. An important avenue for accomplishing this is through prevention interventions that develop knowledge, skills, and competencies in the targeted individual(s). This provides the basic rationale for the conception and design of prevention intervention programs.
Design of science-based interventions begins at the theoretical level, with:
- Developmental theories that explain human growth and maturation; the normal course of physical, psychological, emotional, and cognitive changes; and what motivates humans to behave in particular ways
- Ecological theories that specify the contexts within which individuals develop and function and strive to explain the factors within contexts that influence changes in behavior
- Cognitive theories that focus on internal states such as motivation, problem-solving, decision-making, and attention
- Behavior analytic theories that focus on how behaviors and habits are acquired and can be changed
These theories help researchers think about how patterns of behaviors develop, what motivates individuals to behave in specific ways, and what risk and protective factors should be examined. The influence of theory can be traced throughout the processes of conceptualizing, developing, and testing an intervention. Theory informs thinking about what internal and contextual factors and processes may be modifiable; this information is then used in the development of the logic model.
Logic models graphically explain how changes in malleable risk and protective factors and behaviors will take place over time to produce positive outcomes. From the logic model described in “Intervening in Early Childhood” (see “Logic Model for Intervening in Early Childhood to Prevent Drug Abuse”), an intervention is developed, including the specification of knowledge and activities designed to strengthen the resources and capacities identified as crucial to providing protection against and reducing risk factors and associated problem behaviors.
Intervention Timing, Context, and Components
As discussed in “Why is Early Childhood Important to Substance Abuse Prevention?,” life course transitions in childhood often signal new or evolving physical, cognitive, social, and emotional development and represent peak times of vulnerability to various risk factors. Prevention interventions are designed and tested for specific stages of development, with a focus on fostering optimal development as the child encounters new internal and external capacities, social relationships, and contexts. For instance, the expectations for performance associated with new phases of life can trigger anxiety and self-doubt among many children. Providing experiences with and practice in negotiating new situations during these transitions can foster confidence and competence, thereby maximizing the potential for optimal development.
As was described in “Intervening in Early Childhood,” interventions are generally targeted to the context that is most central to the target population—the proximal context. The most important context of very early development is the family, and thus this is the focus of prevention interventions for the prenatal through infancy and toddlerhood periods. Interventions may be delivered in the home or in other contexts with which families interact.* Other contexts, like school, become increasingly important for children at older ages.
Intervention components specify what knowledge, skills, and competencies are addressed in an intervention to achieve the target outcome. Components are specific to target populations and, within an intervention, multiple actors may be defined as target populations. For example, family-based programs often include parent and child behavioral outcomes and classroom interventions often include both teacher and child outcomes. Moreover, interventions that combine contexts—such as family and school—could target the child, the caregivers, and the teachers. Thus, the targeted knowledge, skills, and competencies would be specific to those intervention populations and can be very precisely defined.
The diagram “How Interventions Work” illustrates several key features that help in understanding how interventions work. Moderators are aspects of the people who are targeted by the intervention and influence the intervention’s design and outcomes but cannot be changed—such as age, sex, race, and socio-economic factors such as poverty. Modifiable risk factors are the knowledge, behaviors, attitudes, intentions, skills, and competencies that the intervention attempts to change. The intervention often includes:
- activities designed to promote skill development in specific areas such as parenting
- environmental change strategies, such as modifying classroom management style to reduce the aggressive behaviors of some children
- provision of services to help in the development of specific competencies such as academic skills through tutoring
- community-level change strategies such as changing minors’ access to alcohol or tobacco through policy enforcement
* This is the case with two examples of the NIDA-supported interventions for children under the age of 3. The Nurse Family Partnership intervention (www.nursefamilypartnership.org) sends nurses to the home to train young mothers and can take advantage of the public health system for implementation. The Early Steps intervention screens for mothers in need of services through an existing program for at-risk families called Women, Infants, and Children (WIC), who are then visited, usually in the home, by a trained clinician. Together they decide what resources and services would be most helpful for the child and family.
Program Evaluation and Assessment of Benefit-Cost
Prevention interventions developed using scientific methods go through these stages of theory and logic model conceptualization. In addition, they are subjected to testing, usually in a randomized controlled trial (RCT) or other rigorous research design. An RCT randomly assigns participants to intervention and control conditions. The advantage of this method and other rigorous research designs is that they make it possible to draw conclusions about the effectiveness of an intervention without being concerned that the outcomes are related to some other population or contextual factor that was not taken into account.
Through the evaluation and comparison of measures of current status among intervention and control group participants at multiple time points before, during, and after the intervention, changes in behaviors, attitudes, intentions, skills, and knowledge can be assessed to determine if the expected positive results were achieved.
Continued assessment of intervention-group children and families and comparison with control-group families into adolescence—and in some cases, into early adulthood and beyond—allows researchers to draw conclusions about the impact of intervening in early childhood on outcomes across the course of development, including effects on the initiation or reduction of drug use and related problems. Long-term follow-up of study participants informs understanding of program effects and provides information that can be used to determine the benefits of early interventions relative to their costs. Some of the existing research has not yet been able to follow participants to the point at which drug use, abuse, and addiction occur; for such programs, the assessment of benefit-cost must be estimated. Participants in other programs have been followed into adolescence and young adulthood, and researchers have been able to directly measure outcomes such as drug involvement, educational attainment, criminality, mental health problems, and health-risking sexual behaviors. When this is the case, a direct comparison of those who received an intervention versus those who did not receive it can determine the benefit-cost of the program in preventing negative and promoting positive outcomes.
- Benefit-Cost Examples for Early Childhood Programs
Research on the benefits relative to costs of early childhood prevention interventions has shown positive results. Some examples of benefit-cost data of interventions with long-term follow-up data are:
- Durham Connects—$3.02 saved for each dollar invested (Dodge et al., 2013b)
- Nurse Family Partnership—$2.88 saved for each dollar invested (Aos et al., 2004)
- Seattle Social Development Project—$3.14 saved for each dollar invested (Aos et al., 2004)
- Good Behavior Game (used in the Classroom-Centered Intervention)—$25.92 saved for each dollar invested (Aos et al., 2004)
Other programs with long-term follow-up data have not shown benefits this dramatic. However, the listed examples point out the extent to which a well-conceptualized and implemented intervention for very young children can benefit society tangibly, not to mention the improved quality of life for children and families that comes from preventing substance abuse and other problems. The tables below indicate which of the early interventions included in this review have economic analysis information (e.g., cost, benefit-cost, or cost effectiveness analysis).
Infancy and Toddlerhood
Program Economic Analysis Information Available? Type of Information Durham Connects Yes Cost of the intervention; benefit-cost analysis; Emergency health care service savings(Dodge et al., 2013b) Early Steps, Family Check-Up No Family Spirit No Nurse Family Partnership Yes Savings in government spending (Olds et al., 2010)
Benefit-cost analysis (Karolyv et al., 2005; Aos et al., 2004)
Program Economic Analysis Information Available? Type of Information Incredible Years-Spirit No Multidimensional Treatment Foster Care for Preschoolers No
Transition to Elementary School
Program Economic Analysis Information Available? Type of Information Caring School Community Program No Classroom-Centered Intervention (Good Behavior Game) Yes Benefit-cost analysis (Aos et al., 2004; Miller & Hendrie, 2008) Linking the Interests of Families and Teachers No Raising Healthy Children No SAFEChildren Yes Cost of program (National Registry: SAFEChildren, 2014) Seattle Social Development Program Yes Benefit-cost analysis(Aos et al., 2004; Miller & Hendrie, 2008) Early Risers "Skills for Success" Risk Prevention Program Yes Cost of program (National Registry: Early Risers, 2014) Kids in Transition to School No Fast Track Trial for Conduct Problems Yes Cost of conduct problems (Foster & Jones, 2005)
Cost effectiveness analysis (Foster et al., 2006)
Incredible Years Yes Cost effectiveness analysis (Foster et al., 2007) Positive Action Yes Cost of program (National Registry: Positive Action, 2014) Schools and Homes in Partnership No
- Selected References
- Aos S, Lieb R, Mayfield J, Miller M, Pennucci A. Benefits and costs of prevention and early intervention programs for youth. Olympia, WA: Washington State Institute for Public Policy; 2004. Document No. 04-07-3901. http://www.wsipp.wa.gov/ReportFile/881/Wsipp_Benefits-and-Costs-of-Prevention-and-Early-Intervention-Programs-for-Youth_Summary-Report.pdf. Published September 17, 2004. Accessed February 3, 2015.
- Dodge KA, Goodman WB, Murphy RA, O’Donnell K, Sato J. Randomized controlled trial evaluation of universal postnatal nurse home visiting: impacts on child emergency medical care at age 12-months. Pediatrics. 2013;132:S140-S146.
- Foster EM, Jones DE. The high costs of aggression: public expenditures resulting from conduct disorder. Am J Public Health. 2005;95(10):1767-1772.
- Foster EM, Jones D, Conduct Problems Prevention Research Group. Can a costly intervention be cost-effective? An analysis of violence prevention. Arch Gen Psychiatry. 2006;63(11):1284-1291.
- Foster EM, Olchowski AE, Webster-Stratton CH. Is stacking intervention components cost-effective? An analysis of the Incredible Years program. J Am Acad Child Adolesc Psychiatry. 2007;46(11):1414-1424.
- Karoly LA, Kilburn MR, Cannon J. Early Childhood Interventions: Proven Results, Future Promise. Santa Monica, CA: RAND Corporation; 2005.
- Miller T, Hendrie D. Substance Abuse Prevention Dollars and Cents: A Cost-Benefit Analysis. Rockville, MD: Center for Substance Abuse Prevention, Substance Abuse and Mental Health Services Administration; 2008. HHS Pub. No. (SMA) 07-4298. https://www.samhsa.gov/sites/default/files/cost-benefits-prevention.pdf.
- National Registry of Evidence-Based Programs and Practices. Intervention Summary: SAFEChildren. Rockville, MD: Substance Abuse and Mental Health Services Administration; 2014. Reviewed: October 2007.
- National Registry of Evidence-Based Programs and Practices. Intervention Summary: Early Risers “Skills for Success.” Rockville, MD: Substance Abuse and Mental Health Services Administration; 2014. Reviewed May 2007.
- National Registry of Evidence-based Programs and Practices. Intervention Summary: Positive Action. Rockville, MD: Substance Abuse and Mental Health Services Administration; 2014. Reviewed December 2006.
- Olds DL, Kitzman H, Cole R, et al. Enduring effects of prenatal and infancy home visiting by nurses on maternal life course and government spending: follow-up of a randomized trial among children at age 12 years. Arch Pediatr Adolesc Med. 2010;164(5):419-424.