Backward linkages characterize the relationship of an industry or institution with its supply chain.  An Industry has significant backward linkages when its production of output requires substantial Intermediate Inputs from many other industries within the same study area.  In the standard  I-O model, Type I multipliers are measures of such backward linkedness.  Type SAM multipliers expand on these inter-industry linkage effects to include household spending effects.  Learn more at Key Assumptions of IMPLAN & Input-Output Analysis.