RESUMEN
Water, sanitation, and hygiene (WASH) interventions prevent and control disease in humanitarian response. To inform future funding and policy priorities, WASH 'gaps' were identified via 220 focus-group discussions with people affected by crises and WASH practitioners, 246 global survey respondents, and 614 documents. After extraction, 2,888 (48 per cent) gaps from direct feedback and 3,151 (52 per cent) from literature were categorised. People affected by crises primarily listed 'services gaps', including a need for water, sanitation, solid waste disposal, and hygiene items. Global survey respondents principally cited 'mechanism gaps' in providing services, including collaboration, WASH staffing expertise, and community engagement. Literature highlighted gaps in health (but not other) WASH intervention impacts. Overall, people affected by crises wanted the 'what' (services), responders wanted the 'how' (to supply), and researchers wanted the 'why' (health consequences). This study suggests a need for a renewed focus on basic WASH services, collaboration across stakeholders, and research on WASH outcomes beyond health.