This paper analyses changes in multidimensional poverty over time for over thirty countries and 338 subnational regions, for which have comparable data across at least two periods of time. The paper first describes the absolute and relative changes in the multidimensional poverty index (MPI) and their significance, as well as changes in the composition of multidimensional poverty. In so doing demonstrates the core statistics of dynamic multidimensional poverty analyses. Second, the paper examines changes in the MPI and its consistent partial indices over time across over 338 sub-national regions, plus a diversity of ethnic groups. In each case it identifies regions or ethnic groups where national poverty reduction is at risk of leaving the poorest subgroups behind. This extensive body of empirical evidence points to some fundamental research questions on the study of multidimensional poverty reduction.