A decision support system (DSS) helps people come up with a decision by giving people the proper information and a suggested answer; while this can be helpful, there are several drawbacks. One of the disadvantages of decision support systems is that they can stop the user from thinking and may promote a cognitive bias. Users can receive an information overload, which decreases decision-making effectiveness. If a decision goes wrong, some users may shift responsibility onto the DSS, rather than blaming themselves. DSS programs without enough data also may make poor decisions, because they do not fully understand the situation.
Most DSS users are professional managers or decision makers who are trained not to rely on DSS programs, because the program is intended only to assist in making a decision. Some users may be prone to place a lot of trust in the DSS, because a computer can look at facts without bias. This may be taken to an extreme, and users may stop thinking, choosing instead to trust the computer exclusively. While this is one of the disadvantages of decision support systems, another is that users may create cognitive biases. For example, an intuitive and perceptive thinker may become overly judgmental and factual after interacting with a DSS.
When users seek a decision from a DSS, the program often gives users information in databases and graphs to help support the decision. Normally, if the information is easily digestible, this will help users make informed decisions, because they will know all the facts and data stored in the DSS database. At the same time, information overload can be one of the disadvantages of decision support systems. If the DSS supplies large databases that take hours or days to read, then users spend more time looking over facts and trying to remember all the information, instead of making a decision. Aside from the information overload, this can decrease decision-making effectiveness.
Without a DSS, a person who makes a wrong decision can only blame himself; this normally causes the person to understand what went wrong in the decision, so he can better approach a similar situation in the future. DSS programs can offset this responsibility, especially if the user places an unusual amount of trust in the program. Instead of assigning the blame to himself, the user may blame the DSS. The personal growth that could have occurred from understanding the poor decision may instead result in the user learning how to blame the computer for any decision-making shortcomings.
Just like people, a DSS needs information to make accurate and informed decisions. If a DSS is new or has a small or inaccurate database, then it may be prone to inaccuracy. Unless the DSS has all the specific information needed to make a decision, the system should not be fully trusted, because any decisions or suggestions may be very wrong. This becomes another of the major disadvantages of decision support systems.