City resilience describes the capacity of cities to function, so that communities, business and government survive and thrive no matter what stresses or shocks they encounter. From its early conceptual beginnings within the field of ecology in the 1970s, ‘resilience' has been understood as the capacity of a system or agent to maintain or recover functionality in the event of disruption or disturbance.

Current approaches that apply this concept to cities view resilience as a process of evolution. Recent shocks suffered by cities -such as, Hurricane Katrina in New Orleans, 2005; bushfires in Victoria, 2009; and Superstorm Sandy in New York, 2012 - have highlighted the urgent need to translate this evolutionary approach into action. However, turning the concept of resilience into practice, particularly in cities, is a challenge not yet addressed by political leaders, academics and practitioners.

This paper will share the preliminary results of a research project[1] carried out by Arup in collaboration with the Rockefeller Foundation. The project's focus is on creating an outcomes-based framework for understanding city resilience, which will ultimately result in a measurable ‘index' for each city which can guide progress and inform urban investment decisions. Building on a comprehensive literature review, case studies, and primary evidence gathered from government, business, and communities in six cities world-wide, this tool aims at helping city governments and other urban actors to define a trajectory of resilience by defining outcomes, measuring progress, and identifying current gaps and opportunities.