The Grand Uncertainties Matrix (the “GUM”) is a collection of the uncertainties, questions, and unknowns that hamper or impede recovery planning and implementation, and therefore overall ecosystem recovery. The need to organize and resolve these uncertainties in an intentional and systematic way is the reason the GUM was developed. The GUM serves as the primary repository for the National Estuary Program to organize, scope, prioritize, and resolve uncertainties for the recovery of Puget Sound. The primary source of individual uncertainties in the GUM are the Puget Sound Implementation Strategies. The GUM was conceived of and is managed by the University of Washington Puget Sound Institute. 

--Source: Puget Sound Institute.