An Invitational Conference
FBI Academy, Quantico, VA
Feb 28, 2002
Sponsored by the FBI Behavioral Science Unit
The FBI's Behavioral Science Unit identifies decision tree techniques and data mining as "highly efficient methods for processing large volumes of data." However, they add that they need to be "tailored to the unique cultures in which they would be used," and that their use depends on a cooperative effort by those that design such methods with those who have to analyze them. The decision tree decision-making methodology is recognized by the FBI as one method to standardize responses to threats and to understand the seriousness of those threats.
After collaboration efforts to receive and organize incoming information have been established with a technical advisor and a decision tree has been created, using the decision tree can be broadly applied due to it's low technical skill demands. The FBI also adds that decision trees should serve only to report information to a decision maker, reinforcing the idea that decision trees should be suggestive - not to actually state the decision to be made.
Appendix 6 gives the most useful information regarding decision tree analysis. In this appendix, it defines decision trees as a tool to aid decision making. "The idea is to concretely identify the choice points and map the sequence of decisions from beginning to end."
- Started with a decision that must be made - the FBI uses the example of whether or not to arrest a suspect. Represent this decision with a square. This should be drawn on the left-most side of the paper/screen.
- Using lines drawn outward and to the right, identify each possible solution. Write each solution on each line.
- At the end of each line, the results are considered. Use a circle is drawn at the end of the line to identify if choices are available
- If another decision is possible, draw a square with that decision listed.
- If there is a final consequence, a solid dot is drawn with a filled-in circle at its end.
The FBI identifies the procedure for choosing a decision as backward induction analysis. In order to do this first assign a number that represents the worth or utility of the final consequence (filled-in circle). Use a 0.0 to 1.0 scale to identify worth. Next, assign a sum to each event node (the circles) that represents the expected utility of the node - this is the weighted average utility for that event node. "Finally, each decision node is a assigned a number that is the maximum value of the nodes that branch out from it."
According to the Behavioral Science Unit the benefits of using decision tree analyses are: 1) that the possible choices are explicitly made; 2) the choices are evaluated by the importance of the outcome as well as quantified with the probability for that outcome; and, 3) displays communication flow.
The FBI, once again, states that "decision trees can be used to guide decisions, not make them. The final decision is left up to the operator."