Final answer:
A Decision Support System (DSS) is most needed for unique, rapidly changing, and complex decisions that cannot be easily specified in advance. It helps in compiling and analyzing data from various sources to aid in problem-solving and decision-making.
Step-by-step explanation:
When faced with decisions that are unique, rapidly changing, and not easily specified in advance, the type of support system that is most needed is a Decision Support System (DSS). These are interactive software-based systems intended to help managers compile useful information from a combination of raw data, documents, personal knowledge, or business models to identify and solve problems and make decisions. Management Information Systems (MIS) are more suitable for structured decision-making processes, while Executive Information Systems (EIS) are designed to provide senior executives with information relevant to strategic decision-making. Transaction Processing Systems (TPS) are used to collect, store, modify and retrieve the transactions of an organization.
Decision Support Systems are crucial in the Information Age, where information overload can make decision-making processes more complex. Despite often lacking perfect information, or 'imperfect' information as economists describe, individuals and organizations must still make numerous decisions based on the best available data. With the aid of DSS, it becomes easier to handle complex and rapidly evolving scenarios that would otherwise be daunting due to the volume and variability of information that is characteristic of such situations.