A system model is an abstract representation of a complex social system, which can be useful for facilitated sensemaking and decision support. This study presents a causal model format adapted from causal loop diagramming to integrate more knowledge of complexity, with higher comprehension.

As a case study, a Poverty Reduction Model was developed with over 1100 cause-and-effect relationships between more than 550 factors. Staff of the Yonge Street Mission social services agency used this model to find interventions to reduce poverty in Toronto, which were prioritized using the system model in combination with rating, scoring and discussion.

A framework is provided to balance model scope and quality requirements with the time and resources available to an organization. Modelling and option-comparison methods are documented for potential re-use by other organizations.

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