Decision trees are an effective way of organising reasoning and analysing the problem. A clear identification of a sequence of events and the links between them makes problematic decisions much easier to understand and manage. By making estimates of the probability [likelihood] and desirability of consequences explicit in numbers, it is possible to work out which option has the highest value and show the grounds for the final choice.
In your small group, identify a decision that needs to be made in the case and have a go at using the decision tree to decide which is the strongest option. You can download the instructions and example from the materials tab.