Programs targeted toward at-risk individuals or populations to prevent the development of social adjustment problems, injuries and illnesses, as well as disabilities and disorders more generally. Sometimes referred to as primary intervention (intervening before a problem has arisen) in contrast to secondary intervention (intervening while a problem is developing), and tertiary intervention (intervening after a problem has become manifest). A major concern in establishing (health-based) programs of intervention is to ensure that they are founded by evidence-based policy instead of policy-based evidence. Such has not been the case with, for example, with some work-to-welfare programs in both the UK and US.
See Ages and Stages Questionnaire (ASQ), Disability, Disorder, Efficacy, IDEA, Intervention study, Longitudinal-exerimental studies, Welfare-to-work studies