Extant research has primarily focused on characterizing input elements, typically referred to as pillars, of metropolitan entrepreneurial ecosystems (e.g., Isenberg, 2010; Vogel, 2013). In comparison, we know far less about the performance of ecosystems. The few studies that do exist are limited in that they are: a) descriptive and not based on statistical analyses, b) usually cross- sectional in nature and c) are case-based and hence hard to generalize. In this study, we aim to overcome these issues by conducting a historical assessment of U.S. metropolitan ecosystems, with archival data from 1998-2012.