There are more young people in the world today than ever before. Yet surprisingly little is known about the current state of affairs in youth development. Measuring the well-being of young people continues to be a challenge, even though its importance is widely recognised. The Commonwealth's youth flagship report, the Global Youth Development Index and Report, provides an evidence-based overview of the state of development for the nearly 1.8 billion young people between the ages of 15 and 30 in the world. The Youth Development Index (YDI) is a composite index of 18 indicators that...