**5. Seeing cities as complex systems**

ABAs, discussed above, are intended as an approach that is people-centred, while acknowledging the complexities of city life. This section further develops this theme, that an understanding that builds resilience in recovery is one that indeed embraces and works with complexity—when an overly simplistic approach to recovery is taken that does not recognise complexity, then affected people's agency, ownership and ability can be eroded, which ultimately harms resilience.

Cities are inevitably complex—infrastructure, density, verticality, diversity, scale, commerce, culture, markets, inequality and entrepreneurship are just some of the words associated with 'urban'. As noted above, the humanitarian system prefers simplicity. Derived mostly from providing goods and services to affected populations mostly in poor, rural settings, the 'urbanisation' of humanitarian aid itself has been a journey of some decades, and one which has gathered momentum in humanitarian circles, in particular since the 2010 Haiti earthquake [23].

In recent years, seeing cities in terms of systems has also gained popularity (see e.g. the work of the Rockefeller Foundation's 100 Resilient Cities programme). Systems can be defined as 'an interconnected collection of things organised in a pattern or structure that changes frequently' [24, 25]. There are different interpretations for classifications of urban systems. Campbell [24] identifies five interconnected urban systems: politics and governance; economy and livelihoods; infrastructure and services; space and settlements; and, social and cultural systems [24, 25]. UN-Habitat identifies five attributes of urban systems—functions (such as governance and social processes), organisations, space, physicality and change over time [26]. A systems view of the city—if used as a basis for recovery planning—can help to avoid overly simplistic approaches that provide little help in the long run. If a water supply is

needed, does an implementing agency pay water vendors to provide water, dig bore holes, mend pipes and/or support the reconstruction of a municipal water supply? Whichever option or options an implementing agency chooses, in collaboration with others, a better understanding of the strategic impact of their efforts through a systems lens should help.

A further example is health. The World Health Organisation (WHO) emphasises the need to understand urban healthcare in terms of systems, comprising six inter-related subsystems—governance, health financing, health workforce, service delivery, essential medicines and technology and health information systems [27]. Providing immediate and longer-term health provision post-disaster is often vital, but a risk for agencies is ignoring the existing health systems—hospitals, doctors, nurses, health centres—that already exist and who need to be engaged with, and not ignored. A wide-ranging review of good practice in urban disaster recovery undertaken by the author concluded that good practice in health response 'includes prioritising working through, rebuilding or improving pre-existing healthcare systems as early as possible. Health interventions must be sustainable, and must not be seen purely as short-term life-saving measures built in parallel, as they then undercut existing systems. This can be as devastating as the disaster itself, taking years to recover' [28].

Perhaps one of the most effective approaches in disaster recovery that builds people's agency (and therefore contributes to resilience) is cash-based programming, that is providing cash to disaster-affected people. Cash as a programming approach has grown rapidly over the last few years. Cash gives agency to people to prioritise their own needs. It supports urban systems such as local markets, supporting traders and commerce. Cash programming also has low transaction costs (sending money is much cheaper than sending food). Cash has obvious resonance in urban areas where markets exist—it has been argued that cash transfers should be the primary response in urban areas [29].
