A management information systems helps manager make decisions by providing information from a database with little or no analysis. A decision support system (DSS), on the other hand, helps managers make decisions by analyzing data from a database and providing the results of the analysis to the manager. An MIS supports all three levels of management decision making with reports and query responses. A DSS, on the other hand, is usually best for decisions at the middle and top levels of management. As with an MIS, a DSS helps with making decision but does not actually make decision; only managers make decisions.
The users of a DSS are managers, usually at the tactical and strategic levels in the organization. The user requests analysis of data from the system, and the results of the analysis are displayed on the user’s screen or printed in a report. The DSS database contains data that is analyzed to produce the output. The DSS model base (analogous to a database) contains the mathematical models and statistical calculation routines that are used to analyze data from the database. The DSS software provides capabilities for the user to access data in the database and to use models from the model base to analyze the data. The software also displays the result of the analysis on the screen or prints it on paper. Often, the output from a DSS is given in a graphic form, although other forms of output are used. Using the software, the user can try different models and data to see what happens.
The data for the DSS database comes from several sources. The user may enter data into the database, or data may be retrieved from the MIS database or the transaction processing system stored data. In addition, the results of a previous analysis by the DSS may be stored in the database for use in later analysis. External sources may also be used to supply data for the DSS database.
An example of a DSS is one that helps a manager in an athletic shoe store decide what types of shoes to advertise. The system would use data from a database containing past sales of different types of shoes. The sales data would be analyzed by statistical calculation routines to project sales trends. Then, a mathematical model would be used to simulate the effect of advertising on sales. The manager would try different strategies until he or she found the one that was most likely to increase sales.
Decision support system are best used for situations in which decisions are semi-structured or unstructured. The nature of these decisions often involves trying different approaches, asking what-if questions, finding input values that produce a specific output (a process called goal seeking), and checking the result to see how it might change if the input were slightly different (a process called sensitivity analysis.) The types of decisions that fit this situation are not made very frequently and often affect business for some time. All these characteristics point to the use...