This special edition of The State of the World's Children will highlight the critical role data and monitoring play in realising children's rights. With reliable data, analysed and disseminated effectively, monitoring makes it impossible for the denial of rights to go unnoticed. Data do not, of themselves, change the world. They make change possible - by identifying needs, supporting advocacy, gauging progress and holding duty-bearers to account. Making the possible real is up to decision-makers. The essay also calls for greater investment - both in disaggregated data and data on previously uncounted children - so that efforts and initiatives may be better targeted to reach the most excluded. Contains an essay (4,500 words), 14 statistical tables, graphics and photos.