In READ, methods were devised for identifying the dominant centers of each area of the West and then further identifying adjacent and nearby counties that can be considered "closely-linked" to these centers, both economically and socially, by their proximity. A "top-down," step-by-step approach was used that begins with the very largest cities and their surrounding counties and then moves to progressively smaller centers that serve as the "hubs" of increasingly less-populated areas. Cities that serve as hubs vary greatly in size, depending on their proximity to other larger cities. The "real" populations of many western cities also stretch well beyond their city limits, so the populations of the counties in which hub cities are found are used in the READ region classification scheme. These counties are referred to as region "cores" and their populations vary from several million people, like Los Angeles County, California, to less than 30,000 people, like Ford County, Kansas; home county of Dodge City.

A "hierarchy" of regional centers and region types is visualized under READ, reflecting an "urban-rural continuum" of sorts, ranging from major metro centers and their surrounding closely-linked metropolitan areas to what can be thought of as "2nd" and "3rd" tier metro centers that are progressively smaller in population size and economically complexity. Still lower in this hierarchy are even smaller, largely non-metro regional centers and their surrounding areas and, lower yet, progressively smaller centers as small as 10,000 people. Beyond these regional centers and their surrounding regions are many smaller, more remote and sparsely-populated areas that have no place or city of sufficient size to serve as a region center. These are classified as "isolated rural counties" and the structure and direction of change in the economies of these areas is heavily influenced by their relative isolation.