The importance of contingent relationships between variables influencing MIS implementations has often been emphasized. This study tests ten propositions regarding the contingent relationships influencing the implementation of a certain class of information systems, generally called Decision Support Systems (DSS). These propositions are derived from a contingency framework that groups the variables relevant to DSS implementations into four categories. These are the characteristics of: the decision maker/user, the DSS, the decision environment, and the implementation process. It is posited that the successful implementation of DSS depends not only on the direct effects of variables in each category, but also on the overall fit between these variables. DSS implementation success is defined as high user satisfaction and system usage.;Based on the proposed framework, ten propositions regarding specific contingent or fit relationships between variable pairs from the four categories of the framework are suggested. Defined as multiplicative effects between the variable pairs concerned, the propositions were tested in a field survey of DSS in 9 organizations from the insurance, banking, and utility industries.;The results of the study indicate that multiplicative effects do not account for a significant portion of the observed variance in the three dependent variables, over and above the portion accounted for by the main effects. The results also show that the main effect variable, DSS flexibility, accounts for nearly half the observed variance in user information satisfaction. These results and the fact that a relatively high proportion of the variance in the three dependent variables was accounted by the main effect variables DSS flexibility, decision maker/user willingness to change, and involvement in implementation, leads to the conclusion that, for DSS implementations, multiplicative effects are unimportant. On the other hand, DSS flexibility appears as a primary consideration to keep in mind in implementing DSS