1. (marketing research definition) A coordinated collection of data, system tools, and techniques with supporting software and hardware by which an organization gathers and interprets relevant information from business and the environment and turns it into a basis for making management decisions. 2. (models definition) A system, usually based on a model and computer software package, that describes the implications of specific marketing decisions and/or recommends specific marketing actions, using a set of input information. This information may either reside permanently in the DSS or be input for the particular scenario of interest (or both). The information can consist of primary information (e.g., sales and cost information from company records, or subjective judgments by managers about the likely impact of increased advertising spending) and/or secondary information (e.g., sales of competitors' products from a syndicated database constructed via store audits). An important aspect of many decision support systems is the facilitation of "what if" analyses; i.e., the sensitivity of optimal marketing strategy to the assumptions in the input information.