The stock synthesis model (Methot 1989, 1990) was developed to provide a bridge between biomass-based assessment methods and full age-structured methods (Deriso et al. 1985; Fournier and Archibald 1982). Subsequently, synthesis evolved to a flexible tool (Methot 1990) and was used for many west coast and Alaska groundf ish stock assessments during 1988-2000. Synthesis consists of a forward population projection model that simulates the dynamics of a stock within a statistical estimation framework. Between the population model and the statistical model is an observation model designed to derive expected values for various fishery and survey data. An underlying philosophy of synthesis is.
