There have been a great many interventions designed to improve the life chances of young children in some way. Few of these have been properly evaluated, and not all have been shown to be effective. This review assesses the research evidence on what types of early interventions are most effective in preventing social exclusion outcomes, such as poor educational achievement. As well as looking at those evaluations that use rigorous experimental designs and have measurable outcomes, it includes some evaluations which are more suggestive of effectiveness but have not been fully evaluated. Interventions are broadly grouped into different tiers according to the intended target of the intervention, and from this some general characteristics of effective interventions are identified, as well as some features associated with the effectiveness of particular types of intervention.