Abstract
Recent disasters have challenged the formal structure of emergency response plans in the U.S. disaster management system. Although major reform efforts have been undertaken over the last twenty years, the actual practice among federal, state, county/parish, and municipal agencies has changed in some instances, not in others. This article presents findings from an unusual quasi-experimental study of four hurricanes - Katrina and Rita that struck the Gulf Coast states of Louisiana and Texas in 2005, and Gustav and Ike that struck the same region in 2008 - to examine the network evolution from implemented changes. The analysis is based on data collected through a content analysis of local newspapers, which identified the organizational interactions that emerged in response operations following each of the hurricanes. These data were then analyzed to compare the four networks of action in terms of centrality, density, distance, and clustering. We next conducted a quadratic assignment procedure (QAP) analysis and a small world network analysis. Findings from the analyses reveal that the response systems in the State of Louisiana successfully achieved network evolution, the result of lessons learned from events in 2005 and implemented prior to 2008. In contrast, the response systems in the State of Texas demonstrated few signs of network evolution between the two storms.