We use detailed data from individuals in multiple organizations to examine the role of information systems (IS) use for decision support, formal processes and social interactions on individual decision making. We found, contrary to our expectations, that the extent of IS use for decision making alone did not significantly influence individual decision making efficacy. However, the extent to which a decision process is defined and operationalized has a significant positive effect on decision making efficacy. In addition, social interactions also influence decision making positively. The joint effect of decision process and social interactions offers a clue to how decision support systems (DSS) can be designed and operationalized. These results not only extend our theoretical understanding of the role of DSSs, they offer insights on how structural improvements can be made to leverage decision making capabilities of individuals in organizations.