The elusive quest for the perfect index of concentration: Reply to Egan, Anderton, and Weber

In this response we correct an error in our earlier description of the RCO index. We also confirm that the index is not bounded on the negative side as we had previously thought, and we discuss the conditions under which its value goes below -1. We consider defining concentration in terms of density rather than area and systematically compare area-and density-based measures. We conclude that in spite of its methodological imperfections RCO remains a useful and informative measure of spatial concentration that can be safely used until a clearly superior alternative is identified.