The third step in the process is to establish a clear evidence base and knowledge bank to establish a baseline for the current challenges of the city, and support evidence-based decision making for future plans and actions. The evidence base may include census and geographical data, hydro-meteorological data, socio-economic data, experience of past disasters, locally-generated and traditional knowledge, and rigorous data and information pertaining to current and future trends and impacts on city systems. Much of this data may already be collected by cities as part of their annual/periodic planning processes. The data used for resilience planning should be reconciled with the planning data to ensure that there is no conflict between the two.
Establishing an evidence base requires recognizing the types of data and information that will be required for planning and subsequent processes (determined in step 2), and also determining sources and methodologies for obtaining the data and information. Municipal governments and city departments may also need capacity building to collect and analyze data effectively. In many cases assistance may be available from other government agencies or from NGOs or private sector entities.