There is a huge amount of mobility around poverty lines: statements such as “31% of people are extremely poor” can be due to many different combinations of chronic poverty, escaping poverty and impoverishment. Although it is now possible to measure this mobility in a few countries, better policy making requires that governments and other stakeholders have much better information about - and causal analysis of - these poverty dynamics. Box 4.2 provides an idea of what the new poverty dynamics goal and targets could look like.