Decision support systems (DSS) offer potential assistance with semi-structured and unstructured problems. DSS handle large amounts of data from different sources, perform complex analysis, and support optimization, satisficing, and heuristic approaches through "what-if" analysis, simulation, and goal-seeking analysis. Group decision support systems (GDSS) contain elements of DSS plus software to effectively support group decision making. Executive support systems (ESS) are specialized DSS that assist senior executives.