While recognizing the need to track and assess change at the national level, READ has been designed to more carefully evaluate sub-national and sub-state trends in the economy only for regions of the western United States; in particular, the 22 contiguous states that are largely west of the Mississippi River. This region is shown in the adjacent map. The West is a large space, with a fewer number of very large cities and metropolitan areas than what is found in the eastern United States. Major cities in the West also tend to be greater distances from one another, leaving large areas with much smaller cities that serve as regional business and economic centers for sometimes relatively large trade regions. This is particularly the case for the vast area that lies well in-land from the Pacific Coast and well west of the Mississippi River.
The goal of READ -- to better organize economic and social data around sub-state regional economies -- is challenging. Cities and counties in the much of the West are not so easily grouped into Census-designated "Metropolitan Areas," even though many areas not so designated may share common characteristics with those of metro areas. While people may be less crowded and cities and towns more spread-out, much economic activity in the West takes place within sub-state economic regions. And these are, in turn, largely centered around major population centers; although there is wide variation in the size and economic complexity of population centers that serve as regional centers.