Dendrogram/Regionalization of U. S. Counties Based upon Migration Flows

Abstract We have obtained a ”hierarchical regionalization” of 3,107 county-level units of the United States based upon 1995-2000 intercounty migration flows. The methodology employed was the two-stage (double-standardization and strong component [directed graph] hierarchical clustering) algorithm described in the 2009 PNAS letter arXiv:0904.4863. Various features (e. g., cosmopolitan vs. provincial aspects) of the regionalization have been discussed in arXiv:0907.2393, arXiv:0903.3623 and arXiv:0809.2768. However, due to the cumbersome (38page) nature of the dendrogram, this interesting tree structure was not readily available for inspection (but see http://www.spatial.ucsb.edu/events/brownbags/docs/2009-2010/Slater-OrdinalHierarchy.pdf). Here, we do directly present this (searchable) dendrogram. An ordinal scale– rather than the originally-derived cardinal scale of the doubly-standardized values–in which groupings/features are more immediately apparent, is employed.