Decision rings: Making decision trees visual and non-mathematical

The decision tree is widely used to represent and solve decision problems. Because it involves the explicit use of mathematics, it tends to be used for technical audiences. This paper presents an alternative way of representing and solving the decision tree for nontechnical audiences. A common step in quantifying a decision tree is to ask subjects to quantify their beliefs about an event using a probability wheel. This procedure implies that subjects do have geometrical intuitions about uncertainties. Our new approach to decision analysis builds on this insight. Instead of representing the tree with lines, we represent the various levels of a decision tree as concentric rings. Specific events are represented as segments in those rings with the size of the segment being proportional to the probability of the event occurring. Payoffs are represented by coloring various segments. The standard expected value calculation of decision analysis corresponds to mixing the colors from outer segments to color inner segments.