Hierarchical livelihood outcomes among co-managed fisheries

•Diagnostic frameworks provide a key link to quantitative analysis social–ecological systems.•Social–ecological systems include a large number of variables interacting horizontally at the same scale and vertically among scales.•Co-managed fisheries resource users perceive benefits from co-management when they are wealthy and involved.•Relationships between wealth and involvement are modified by dependence on marine resources and population size.•Context plays a critical, identifiable role in co-management success. Collaborative management arrangements are increasingly being used in fisheries, yet critical questions remain about the conditions under which these are most successful. Here, we conduct one of the first comprehensive tests of Elinor Ostrom's diagnostic framework for analyzing social–ecological systems to examine how 16 socioeconomic and institutional conditions are related the livelihood outcomes in 42 co-management arrangements in five countries across the Indo-Pacific. We combine recent developments in both theory and modeling to address three key challenges among comparative studies of social–ecological systems: the presence of a large number of explanatory mechanisms, variables operating at multiple scales, and the potential for interactions among socio-economic and institutional factors. We find that resource users were more likely to perceive benefits from co-management when they are more involved in decisions, were aware that humans are causal agents of change in marine systems, were wealthier, were not migrants, were in villages with smaller populations and older co-management arrangements, and had clearly established boundaries. Critically, we quantify a number of key interactions between: wealth, dependence on marine resources, involvement in decision-making, and population size that have strong implications for co-management success in terms of livelihood benefits. This study demonstrates that context plays a critical but identifiable role in co-management success.