“…Empirical studies of agglomeration use a variety of explanatory variables as proxies for these different factors, and examine their impacts on geographic concentration using measures such as the locational Gini coefficient (Krugman, 1991;Audretsch and Feldman, 1996;Jensen and Kletzer, 2006) and the Ellison-Glaeser industry concentration index (Rosenthal and Strange, 2001;Lu and Tao, 2009). More recently, the emphasis has changed from analyzing patterns of agglomeration to 2 coagglomeration in order to shed light on the factors influencing the geographic concentration of industries Overman, 2005, 2008;Ellison, Glaeser, and Kerr, 2010;Kolko;Jofre-Monseny, Marín-López, Viladecans-Marsal, 2011).…”