This collection contains decision nodes grouped together with additional information about their decision variables for comparison.

Here is an example of a decision tree for determining financial risks. It is very easy to follow simply by navigating the nodes, making a decision as to which way to go, until you get to the final answer. In this case, someone is applying for credit and we need to make a decision on their credit worthiness. A decision tree is a great approach to solving this problem:

With this simplistic visual diagram behind us, let's visit the problem we are trying to solve. It's one that all of us developers face (hopefully) from time to time.