Invited commentary: Promotion and prevention in youth development: two sides of the same coin?

This commentary uses the contributions of the 4-H Study of Positive Youth Development as a chance to reflect on the progress of the past two decades and suggest important tasks for the future. Meaningful advances in theory now set the stage for needed work on measurement, evaluation, and understanding of contextual processes. The commentary ends with a plea for an integration of the research and programmatic approaches of promotion and prevention in order to study youth development and implement youth programs.