This paper surveys the evolution of regional authority in 81 OECD, European, Latin American, and South-East Asian countries from 1950 to 2010 in the light of the a new measure (regional authority index, RAI) that we created. Variation across regions shows no signs of declining over time. There has been no convergence in regional government, but continuing, and wide, divergence. Yet this has been an era of regionalization. The scale of change becomes apparent only when one escapes methodological nationalism, which boils regional government down to a limited number of national categories, such as unitary, federal, confederal.
