No matter how much you know, you can't possibly know everything. No one can possibly know all the input to a decision, process all the possible outcomes, and know every output from the final decision. Neither can an Information System. However, it can gather more input, process it faster, and output more alternatives than a human can.
What a machine can't do is make decisions in context. That could be a positive aspect or a drawback. Humans make decisions based on experience and in very distinct ways based on their frame of reference. For instance, some people won't buy a certain type of television because they haven't had "good luck" with that brand before. Based on their experience, they choose a different alternative than another person would. Some people will do careful, extensive research into all the possible models of televisions and make a decision based on that data. Some people will purchase the same brand as the one they already have. Others simply walk into the store and point to the model they want.<a href://www.govindam.org>Govindam</a>