Structural decomposition analysis, which is usually used within an input-output framework, allows changes in economic variables to be broken down into their determinants. Structural decomposition techniques can also be applied in social accounting matrix (SAM) models, which provide a complete representation of circular flow by adding factor-income generation and household-income distribution to the intersectorial transactions. The author uses structural decomposition analysis to reveal the factors that contribute to the changes in SAM multipliers over time. In particular, she analyses how modifying the patterns of intermediate demand, private consumption, and factor-income distribution modifies the income-generation process. Two SAMs are used, one for 1990 and one for 1994, in an empirical application for the Catalan economy. The results show that the regional multipliers in 1994 were smaller than in 1990, mainly because of a reduction in the structural coefficients of the model.