Eliciting and Combining Influence Diagrams: Tying Many Bowties Together

The work presented here is part of a research project to develop decision-support software for case managers in the Kentucky social welfare system. Welfare case managers help their clients plan participation in activities such as volunteer work, job readiness programs, substance abuse counselling, or study in high school or college, for example. The case manager’s advice is guided by her perception of how different client characteristics, as well as the client’s history prior to and within the program, may affect the client’s probability of success in the proposed activities. This paper focuses on knowledge transfer from welfare domain experts to formal representation of the welfare domain. In the process of modelling decision-making in the Kentucky welfare system, we have elicited influence diagrams from multiple welfare case managers. We have developed a distinctive elicitation procedure and influence diagram format, which we refer to as a “bowtie action fragment”. We present the format, the procedure, and a discussion of methods for combining influence diagrams from multiple experts into one consistent and size-bounded diagram.